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Pinto SM, Thakur B, Kumar RG, Rabinowitz A, Zafonte R, Walker WC, Ding K, Driver S, Venkatesan UM, Moralez G, Bell KR. Prevalence of Cardiovascular Conditions After Traumatic Brain Injury: A Comparison Between the Traumatic Brain Injury Model Systems and the National Health and Nutrition Examination Survey. J Am Heart Assoc 2024; 13:e033673. [PMID: 38686872 DOI: 10.1161/jaha.123.033673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/21/2024] [Indexed: 05/02/2024]
Abstract
BACKGROUND The purpose of this study is to compare the prevalence of self-reported cardiovascular conditions among individuals with moderate to severe traumatic brain injury (TBI) to a propensity-matched control cohort. METHODS AND RESULTS A cross-sectional study described self-reported cardiovascular conditions (hypertension, congestive heart failure [CHF], myocardial infarction [MI], and stroke) from participants who completed interviews between January 2015 and March 2020 in 2 harmonized large cohort studies, the TBI Model Systems and the National Health and Nutrition Examination Survey. Mixed-effect logistic regression models were used to compare the prevalence of cardiovascular conditions after 1:1 propensity-score matching based on age, sex, race, ethnicity, body mass index, education level, and smoking status. The final sample was 4690 matched pairs. Individuals with TBI were more likely to report hypertension (odds ratio [OR], 1.18 [95% CI, 1.08-1.28]) and stroke (OR, 1.70 [95% CI, 1.56-1.98]) but less likely to report CHF (OR, 0.81 [95% CI, 0.67-0.99]) or MI (OR, 0.66 [95% CI, 0.55-0.79]). There was no difference in rate of CHF or MI for those ≤50 years old; however, rates of CHF and MI were lower in the TBI group for individuals >50 years old. Over 65% of individuals who died before the first follow-up interview at 1 year post-TBI were >50 years old, and those >50 years old were more likely to die of heart disease than those ≤50 years old (17.6% versus 8.6%). CONCLUSIONS Individuals with moderate to severe TBI had an increased rate of self-reported hypertension and stroke but lower rate of MI and CHF than uninjured adults, which may be due to survival bias.
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Affiliation(s)
- Shanti M Pinto
- Department of Physical Medicine and Rehabilitation University of Texas Southwestern Medical Center Dallas Texas USA
| | - Bhaskar Thakur
- Department of Physical Medicine and Rehabilitation University of Texas Southwestern Medical Center Dallas Texas USA
- Department of Family and Community Medicine University of Texas Southwestern Medical Center Dallas Texas USA
- Peter O'Donnell Jr. School of Public Health University of Texas Southwestern Medical Center Dallas Texas USA
| | - Raj G Kumar
- Department of Rehabilitation and Human Performance Icahn School of Medicine at Mount Sinai New York New York USA
| | - Amanda Rabinowitz
- Moss Rehabilitation Research Institute Elkins Park Pennsylvania USA
- Department of Rehabilitation Medicine Sidney Kimmel Medical College at Thomas Jefferson University Philadelphia Pennsylvania USA
| | - Ross Zafonte
- Department of Physical Medicine and Rehabilitation Harvard Medical School Boston Massachusetts USA
- Spaulding Rehabilitation Hospital Boston Massachusetts USA
- Department of Physical Medicine and Rehabilitation Massachusetts General Hospital & Brigham and Women's Hospital Boston Massachusetts USA
| | - William C Walker
- Department of Physical Medicine & Rehabilitation Virginia Commonwealth University Richmond Virginia USA
- Department of Physical Medicine & Rehabilitation, Richmond VA Medical Center Central Virginia VA Health Care System Richmond Virginia USA
| | - Kan Ding
- Department of Neurology University of Texas Southwestern Medical Center Dallas Texas USA
| | - Simon Driver
- Baylor Scott & White Research Institute Dallas Texas USA
- Baylor Scott & White Institute for Rehabilitation Dallas Texas USA
| | - Umesh M Venkatesan
- Moss Rehabilitation Research Institute Elkins Park Pennsylvania USA
- Department of Rehabilitation Medicine Sidney Kimmel Medical College at Thomas Jefferson University Philadelphia Pennsylvania USA
| | - Gilbert Moralez
- Department of Applied Clinical Research, School of Health Professions UT Southwestern Medical Center Dallas Texas USA
| | - Kathleen R Bell
- Department of Physical Medicine and Rehabilitation University of Texas Southwestern Medical Center Dallas Texas USA
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Pinto SM, Wright B, Annaswamy S, Nwana O, Nguyen M, Wilmoth K, Moralez G. Heart rate variability (HRV) after traumatic brain injury (TBI): a scoping review. Brain Inj 2024:1-22. [PMID: 38590161 DOI: 10.1080/02699052.2024.2328310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 03/05/2024] [Indexed: 04/10/2024]
Abstract
BACKGROUND Heart rate variability (HRV), defined as the variability between successive heart beats, is a noninvasive measure of autonomic nervous system (ANS) function, which may be altered following traumatic brain injury (TBI). This scoping review summarizes the existing literature regarding changes in HRV after TBI as well as the association between measures of HRV and outcomes following TBI. METHODS A literature search for articles assessing 'heart rate variability' and 'brain injury' or 'concussion' was completed. Articles were included if HRV was measured in human subjects with TBI or concussion. Review articles, protocol papers, and studies including non-traumatic injuries were excluded. RESULTS Sixty-three articles were included in this review. Varied methods were used to measure HRV in the different studies. Forty articles included information about differences in HRV measures after TBI and/or longitudinal changes after TBI. Fifteen studies assessed HRV and symptoms following TBI, and 15 studies assessed HRV and either functional or cognitive outcomes after TBI. CONCLUSIONS HRV has been studied in the context of mortality, clinical symptoms, and medical, functional, or cognitive outcomes following TBI. Methods used to measure HRV have varied amongst the different studies, which may impact findings, standardized protocols are needed for future research.
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Affiliation(s)
- Shanti M Pinto
- Department of Physical Medicine and Rehabilitation, O'Donnell Brain Institute Clinical Neuroscience Scholar, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Brittany Wright
- Department of Physical Medicine and Rehabilitation, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Shreyas Annaswamy
- National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, Maryland, USA
| | - Ola Nwana
- Department of Neurology, Houston Methodist Neuroscience Center Team at Willowbrook, Houston, Texas, USA
| | - Michael Nguyen
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas, USA
- Brain Injury and Stroke Medicine, TIRR Memorial Hermann, Houston, Texas, USA
| | - Kristin Wilmoth
- Department of Physical Medicine and Rehabilitation, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Belval LN, Cramer MN, Moralez G, Huang DPT M, Watso JC, Fischer M, Crandall CG. Burn size and environmental conditions modify thermoregulatory responses to exercise in burn survivors. J Burn Care Res 2024; 45:227-233. [PMID: 37615621 PMCID: PMC10768759 DOI: 10.1093/jbcr/irad128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Indexed: 08/25/2023]
Abstract
This project tested the hypothesis that burn survivors can perform mild/moderate-intensity exercise in temperate and hot environments without excessive elevations in core body temperature. Burn survivors with low (23 ± 5%TBSA; N = 11), moderate (40 ± 5%TBSA; N = 9), and high (60 ± 8%TBSA; N = 9) burn injuries performed 60 minutes of cycle ergometry exercise (72 ± 15 watts) in a 25°C and 23% relative humidity environment (ie, temperate) and in a 40°C and 21% relative humidity environment (ie, hot). Absolute gastrointestinal temperatures (TGI) and changes in TGI (ΔTGI) were obtained. Participants with an absolute TGI of >38.5°C and/or a ΔTGI of >1.5°C were categorized as being at risk for hyperthermia. For the temperate environment, exercise increased ΔTGI in all groups (low: 0.72 ± 0.21°C, moderate: 0.42 ± 0.22°C, and high: 0.77 ± 0.25°C; all P < .01 from pre-exercise baselines), resulting in similar absolute end-exercise TGI values (P = .19). Importantly, no participant was categorized as being at risk for hyperthermia, based upon the aforementioned criteria. For the hot environment, ΔTGI at the end of the exercise bout was greater for the high group when compared to the low group (P = .049). Notably, 33% of the moderate cohort and 56% of the high cohort reached or exceeded a core temperature of 38.5°C, while none in the low cohort exceeded this threshold. These data suggest that individuals with a substantial %TBSA burned can perform mild/moderate intensity exercise for 60 minutes in temperate environmental conditions without risk of excessive elevations in TGI. Conversely, the risk of excessive elevations in TGI during mild/moderate intensity exercise in a hot environment increases with the %TBSA burned.
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Affiliation(s)
- Luke N Belval
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX 75231, USA
| | - Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX 75231, USA
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX 75231, USA
- Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mu Huang DPT
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX 75231, USA
- Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Joseph C Watso
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX 75231, USA
| | - Mads Fischer
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, DK 1165, Denmark
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX 75231, USA
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Atkins WC, Romero SA, Moralez G, Huang M, Cramer MN, Foster J, McKenna ZJ, Crandall CG. Attrition of Well-Healed Burn Survivors to a 6-Month Community-Based Exercise Program: A Retrospective Evaluation. J Burn Care Res 2023; 44:1478-1484. [PMID: 37166163 PMCID: PMC10628515 DOI: 10.1093/jbcr/irad063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Indexed: 05/12/2023]
Abstract
The purpose of this study was to evaluate whether burn survivors have lower adherence compared to non-burned control individuals during a 6-month community-based exercise program. In burn survivors, we sought to answer if there was a relation between the size of the burn injury and dropout frequency. Fifty-two burn survivors and 15 non-burned controls (n = 67) were recruited for a 6-month community-based (ie, non-supervised), progressive, exercise training program. During the exercise program, 27% (ie, 4 of the 15 enrolled) of the non-burned individuals dropped out of the study, while 37% (ie, 19 of the 52) of the burn survivors dropped out from the study. There was no difference in the percentage of individuals who dropped out between groups (P = .552). There was no difference in size of the burn injury, expressed as percent body surface area burned (%BSA) between the burn survivors that dropped out versus those who completed the exercise regimen (P = .951). We did not observe a relation between %BSA burned and dropouts (log odds = -0.15-0.01(%BSA), B = -0.01, SE = 0.015, P = .541). There was no effect of %BSA burned on the probability of dropout [Exp (B) = 0.991, 95% CI (0.961, 1.020)] and there were no differences in the percentage of individuals who dropped out of the study based on %BSA burned (χ2(1) = 0.44, P = .51). These data demonstrate that burn survivors have similar exercise adherence relative to a non-burned group and the extent of a burn injury does not affect exercise program adherence.
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Affiliation(s)
- Whitley C Atkins
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Steven A Romero
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Gilbert Moralez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Mu Huang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Office of Science, Medicine, and Health, American Heart Association, Dallas, Texas, USA
| | - Matthew N Cramer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Josh Foster
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Zachary J McKenna
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Craig G Crandall
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Watso JC, Romero SA, Moralez G, Huang M, Cramer MN, Jaffery MF, Balmain BN, Wilhite DP, Babb TG, Crandall CG. Six Months of Exercise Training Improves Ventilatory Responses during Exercise in Adults with Well-Healed Burn Injuries. Med Sci Sports Exerc 2023; 55:765-776. [PMID: 36729937 PMCID: PMC10106361 DOI: 10.1249/mss.0000000000003099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
INTRODUCTION Pulmonary function is lower after a severe burn injury, which could influence ventilatory responses during exercise. It is unclear whether exercise training improves pulmonary function or ventilatory responses during exercise in adults with well-healed burn injuries. Therefore, we tested the hypothesis that exercise training improves pulmonary function and ventilatory responses during exercise in adults with well-healed burn injuries. METHODS Thirty-nine adults (28 with well-healed burn injuries and 11 non-burn-injured controls) completed 6 months of unsupervised, progressive exercise training including endurance, resistance, and high-intensity interval components. Before and after exercise training, we performed comprehensive pulmonary function testing and measured ventilatory responses during cycling exercise. We compared variables using two-way ANOVA (group-time; i.e., preexercise/postexercise training (repeated factor)). RESULTS Exercise training did not increase percent predicted spirometry, lung diffusing capacity, or airway resistance measures (time: P ≥ 0.14 for all variables). However, exercise training reduced minute ventilation ( V̇E ; time: P ≤ 0.05 for 50 and 75 W) and the ventilatory equivalent for oxygen ( V̇E /V̇O 2 ; time: P < 0.001 for 75 W) during fixed-load exercise for both groups. The ventilatory equivalent for carbon dioxide ( V̇E /V̇CO 2 ) during exercise at 75 W was reduced after exercise training (time: P = 0.04). The percentage of age-predicted maximum heart rate at the ventilatory threshold was lower in adults with well-healed burn injuries before ( P = 0.002), but not after ( P = 0.22), exercise training. Lastly, exercise training increased V̇E and reduced V̇E /V̇O 2 during maximal exercise (time: P = 0.005 for both variables). CONCLUSIONS These novel findings demonstrate that exercise training can improve ventilatory responses during exercise in adults with well-healed burn injuries.
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Affiliation(s)
- Joseph C. Watso
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, TX
| | - Steven A. Romero
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX
| | - Gilbert Moralez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, TX
| | - Mu Huang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, TX
- Office of Science, Medicine, and Health, American Heart Association, Dallas, TX
| | - Matthew N. Cramer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - Manall F. Jaffery
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - Bryce N. Balmain
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - Daniel P. Wilhite
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - Tony G. Babb
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - Craig G. Crandall
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, TX
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Simpson LL, Hansen AB, Moralez G, Amin SB, Hofstaetter F, Gasho C, Stembridge M, Dawkins TG, Tymko MM, Ainslie PN, Lawley JS, Hearon CM. Adrenergic control of skeletal muscle blood flow during chronic hypoxia in healthy males. Am J Physiol Regul Integr Comp Physiol 2023; 324:R457-R469. [PMID: 36717165 PMCID: PMC10026988 DOI: 10.1152/ajpregu.00230.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023]
Abstract
Sympathetic transduction is reduced following chronic high-altitude (HA) exposure; however, vascular α-adrenergic signaling, the primary mechanism mediating sympathetic vasoconstriction at sea level (SL), has not been examined at HA. In nine male lowlanders, we measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (ΔFVC) during 1) incremental intra-arterial infusion of phenylephrine to assess α1-adrenergic receptor responsiveness and 2) combined intra-arterial infusion of β-adrenergic and α-adrenergic antagonists propranolol and phentolamine (α-β-blockade) to assess adrenergic vascular restraint at rest and during exercise-induced sympathoexcitation (cycling; 60% peak power). Experiments were performed near SL (344 m) and after 3 wk at HA (4,383 m). HA abolished the vasoconstrictor response to low-dose phenylephrine (ΔFVC: SL: -34 ± 15%, vs. HA; +3 ± 18%; P < 0.0001) and markedly attenuated the response to medium (ΔFVC: SL: -45 ± 18% vs. HA: -28 ± 11%; P = 0.009) and high (ΔFVC: SL: -47 ± 20%, vs. HA: -35 ± 20%; P = 0.041) doses. Blockade of β-adrenergic receptors alone had no effect on resting FVC (P = 0.500) and combined α-β-blockade induced a similar vasodilatory response at SL and HA (P = 0.580). Forearm vasoconstriction during cycling was not different at SL and HA (P = 0.999). Interestingly, cycling-induced forearm vasoconstriction was attenuated by α-β-blockade at SL (ΔFVC: Control: -27 ± 128 vs. α-β-blockade: +19 ± 23%; P = 0.0004), but unaffected at HA (ΔFVC: Control: -20 ± 22 vs. α-β-blockade: -23 ± 11%; P = 0.999). Our results indicate that in healthy males, altitude acclimatization attenuates α1-adrenergic receptor responsiveness; however, resting α-adrenergic restraint remains intact, due to concurrent resting sympathoexcitation. Furthermore, forearm vasoconstrictor responses to cycling are preserved, although the contribution of adrenergic receptors is diminished, indicating a reliance on alternative vasoconstrictor mechanisms.
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Affiliation(s)
- Lydia L Simpson
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Alexander B Hansen
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Sachin B Amin
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Florian Hofstaetter
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University, Loma Linda, California, United States
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, United Kingdom
| | - Tony G Dawkins
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Michael M Tymko
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Justin S Lawley
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States
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Watso JC, Huang M, Hendrix JM, Belval LN, Moralez G, Cramer MN, Foster J, Hinojosa-Laborde C, Crandall CG. Comparing the Effects of Low-Dose Ketamine, Fentanyl, and Morphine on Hemorrhagic Tolerance and Analgesia in Humans. PREHOSP EMERG CARE 2023; 27:600-612. [PMID: 36689353 PMCID: PMC10329983 DOI: 10.1080/10903127.2023.2172493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 01/09/2023] [Accepted: 01/19/2023] [Indexed: 01/24/2023]
Abstract
Hemorrhage is a leading cause of preventable battlefield and civilian trauma deaths. Ketamine, fentanyl, and morphine are recommended analgesics for use in the prehospital (i.e., field) setting to reduce pain. However, it is unknown whether any of these analgesics reduce hemorrhagic tolerance in humans. We tested the hypothesis that fentanyl (75 µg) and morphine (5 mg), but not ketamine (20 mg), would reduce tolerance to simulated hemorrhage in conscious humans. Each of the three analgesics was evaluated independently among different cohorts of healthy adults in a randomized, crossover (within drug/placebo comparison), placebo-controlled fashion using doses derived from the Tactical Combat Casualty Care Guidelines for Medical Personnel. One minute after an intravenous infusion of the analgesic or placebo (saline), we employed a pre-syncopal limited progressive lower-body negative pressure (LBNP) protocol to determine hemorrhagic tolerance. Hemorrhagic tolerance was quantified as a cumulative stress index (CSI), which is the sum of products of the LBNP and the duration (e.g., [40 mmHg x 3 min] + [50 mmHg x 3 min] …). Compared with ketamine (p = 0.002 post hoc result) and fentanyl (p = 0.02 post hoc result), morphine reduced the CSI (ketamine (n = 30): 99 [73-139], fentanyl (n = 28): 95 [68-130], morphine (n = 30): 62 [35-85]; values expressed as a % of the respective placebo trial's CSI; median [IQR]; Kruskal-Wallis test p = 0.002). Morphine-induced reductions in tolerance to central hypovolemia were not well explained by a prediction model including biological sex, body mass, and age (R2=0.05, p = 0.74). These experimental data demonstrate that morphine reduces tolerance to simulated hemorrhage while fentanyl and ketamine do not affect tolerance. Thus, these laboratory-based data, captured via simulated hemorrhage, suggest that morphine should not be used for a hemorrhaging individual in the prehospital setting.
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Affiliation(s)
- Joseph Charles Watso
- Department of Nutrition & Integrative Physiology, Florida State University, Tallahassee, Florida, USA
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Office of Science, Medicine, and Health, American Heart Association, Dallas, Texas, USA
| | - Joseph Maxwell Hendrix
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Anesthesiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Luke Norman Belval
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Matthew Nathaniel Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Josh Foster
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | | | - Craig Gerald Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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McKenna ZJ, Moralez G, Romero SA, Hieda M, Huang M, Cramer MN, Sarma S, MacNamara JP, Jaffery MF, Atkins WC, Foster J, Crandall CG. Cardiac remodeling in well-healed burn survivors after 6 months of unsupervised progressive exercise training. J Appl Physiol (1985) 2023; 134:405-414. [PMID: 36633867 PMCID: PMC9902219 DOI: 10.1152/japplphysiol.00630.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/05/2023] [Accepted: 01/08/2023] [Indexed: 01/13/2023] Open
Abstract
Aerobic exercise is important in the rehabilitation of individuals with prior burn injuries, but no studies have examined whether adult burn survivors demonstrate cardiac remodeling to long-term aerobic exercise training. In this study, we tested the hypothesis that 6 months of progressive exercise training improves cardiac magnetic resonance imaging-based measures of cardiac structure and function in well-healed burn survivors. Secondary analyses explored relations between burn surface area and changes in cardiac structure in the cohort of burn survivors. V̇o2peak assessments and cardiac magnetic resonance imaging were performed at baseline and following 6 months of progressive exercise training from 19 well-healed burn survivors and 10 nonburned control participants. V̇o2peak increased following 6 months of training in both groups (Control: Δ5.5 ± 5.8 mL/kg/min; Burn Survivors: Δ3.2 ± 3.6 mL/kg/min, main effect of training, P < 0.001). Left ventricle (LV) mass (Control: Δ1.7 ± 3.1 g/m2; Burn survivors: Δ1.8 ± 2.7 g/m2), stroke volume (Control: Δ5.8 ± 5.2 mL/m2; Burn Survivors: Δ2.8 ± 4.2 mL/m2), and ejection fraction (Control: Δ2.4 ± 4.0%; Burn Survivors: Δ2.2 ± 4.3%) similarly increased following 6 months of exercise training in both cohorts (main effect of training P < 0.05 for all indexes). LV end-diastolic volume increased in the control group (Δ6.5 ± 4.5 mL/m2) but not in the cohort of burn survivors (Δ1.9 ± 2.7 mL/m2, interaction, P = 0.040). Multiple linear regression analyses revealed that burn surface area had little to no effect on changes in ventricular mass or end-diastolic volumes in response to exercise training. Our findings provide initial evidence of physiological cardiac remodeling, which is not impacted by burn size, in response to exercise training in individuals with well-healed burn injuries.NEW & NOTEWORTHY Aerobic exercise is important in the rehabilitation of individuals with prior burn injuries, but no studies have examined whether adult burn survivors demonstrate cardiac remodeling to long-term aerobic exercise training. In this study, we tested the hypothesis that 6 months of progressive exercise training would improve cardiac magnetic resonance imaging-based measures of cardiac structure and function in well-healed burn survivors. Our findings highlight the ability of exercise training to modify cardiac structure and function in well-healed burn survivors and nonburned sedentary controls alike.
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Affiliation(s)
- Zachary J McKenna
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Gilbert Moralez
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Steven A Romero
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | | | - Mu Huang
- Office of Science, Medicine, and Health, American Heart Association, Dallas, Texas
| | - Matthew N Cramer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Satyam Sarma
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - James P MacNamara
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Manall F Jaffery
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Whitley C Atkins
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Josh Foster
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Craig G Crandall
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
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Fischer M, Moralez G, Sarma S, MacNamara JP, Cramer MN, Huang M, Romero SA, Hieda M, Shibasaki M, Ogoh S, Crandall CG. Altered cardiac β1 responsiveness in hyperthermic older adults. Am J Physiol Regul Integr Comp Physiol 2022; 323:R581-R588. [PMID: 36094450 PMCID: PMC9602700 DOI: 10.1152/ajpregu.00040.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 08/30/2022] [Accepted: 09/06/2022] [Indexed: 11/22/2022]
Abstract
Compared with younger adults, passive heating induced increases in cardiac output are attenuated by ∼50% in older adults. This attenuated response may be associated with older individuals' inability to maintain stroke volume through ionotropic mechanisms and/or through altered chronotropic mechanisms. The purpose of this study was to identify the interactive effect of age and hyperthermia on cardiac responsiveness to dobutamine-induced cardiac stimulation. Eleven young (26 ± 4 yr) and 8 older (68 ± 5 yr) participants underwent a normothermic and a hyperthermic (baseline core temperature +1.2°C) trial on the same day. In both thermal conditions, after baseline measurements, intravenous dobutamine was administered for 12 min at 5 µg/kg/min, followed by 12 min at 15 µg/kg/min. Primary measurements included echocardiography-based assessments of cardiac function, gastrointestinal and skin temperatures, heart rate, and mean arterial pressure. Heart rate responses to dobutamine were similar between groups in both thermal conditions (P > 0.05). The peak systolic mitral annular velocity (S'), i.e., an index of left ventricular longitudinal systolic function, was similar between groups for both thermal conditions at baseline. While normothermic, the increase in S' between groups was similar with dobutamine administration. However, while hyperthermic, the increase in S' was attenuated in the older participants with dobutamine (P < 0.001). Healthy, older individuals show attenuated inotropic, but maintained chronotropic responsiveness to dobutamine administration during hyperthermia. These data suggest that older individuals have a reduced capacity to increase cardiomyocyte contractility, estimated by changes in S', via β1-adrenergic mechanisms while hyperthermic.
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Affiliation(s)
- Mads Fischer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
- Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
| | - James P MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
| | - Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
| | - Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
- Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Steven A Romero
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Michinari Hieda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
- School of Medicine, Kyushu University, Fukuoka, Japan
| | - Manabu Shibasaki
- Department of Environmental Health, Nara Women's University, Nara, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Saitama, Japan
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
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Watso JC, Romero SA, Moralez G, Huang M, Cramer MN, Jaffery MF, Balmain BN, Wilhite DP, Babb T, Crandall CG. Pulmonary Function After Six Months Of Progressive Exercise Training In Adult Burn-injury Survivors. Med Sci Sports Exerc 2022. [DOI: 10.1249/01.mss.0000878548.56816.e3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Watso JC, Romero SA, Moralez G, Huang M, Cramer MN, Johnson E, Crandall CG. Six months of unsupervised exercise training lowers blood pressure during moderate, but not vigorous, aerobic exercise in adults with well-healed burn injuries. J Appl Physiol (1985) 2022; 133:742-754. [PMID: 35952345 PMCID: PMC9484988 DOI: 10.1152/japplphysiol.00181.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/18/2022] [Accepted: 08/08/2022] [Indexed: 11/22/2022] Open
Abstract
Exercise training reduces cardiovascular disease risk, partly due to arterial blood pressure (BP) lowering at rest and during fixed-load exercise. However, it is unclear whether exercise training can reduce BP at rest and during exercise in adults with well-healed burn injuries. Therefore, the purpose of this investigation was to test the hypothesis that 6 mo of unsupervised exercise training reduces BP at rest and during lower-body cycle ergometry in adults with well-healed burn injuries. Thirty-nine adults (28 with well-healed burn injuries and 11 controls) completed 6 mo of unsupervised, progressive exercise training including endurance, resistance, and high-intensity interval components. Before and after exercise training, we measured BP at rest, during fixed-load submaximal exercise (50 and 75 W), during fixed-intensity submaximal exercise (40% and 70% of V̇o2peak), and during maximal exercise on a lower-body cycle ergometer. We compared cardiovascular variables using two-way ANOVA (group × pre/postexercise training [repeated factor]). Adults with well-healed burn injuries had higher diastolic BP at rest (P = 0.04), which was unchanged by exercise training (P = 0.26). Exercise training reduced systolic, mean, and diastolic BP during fixed-load cycling exercise at 75 W in adults with well-healed burn injuries (P ≤ 0.03 for all), but not controls (P ≥ 0.67 for all). Exercise training also reduced mean and diastolic BP during exercise at 40% (P ≤ 0.02 for both), but not at 70% (P ≥ 0.18 for both), of V̇o2peak. These data suggest that a 6-mo unsupervised exercise training program lowers BP during moderate, but not vigorous, aerobic exercise in adults with well-healed burn injuries.NEW & NOTEWORTHY Adults with well-healed burn injuries have greater cardiovascular disease morbidity and all-cause mortality compared with nonburn-injured adults. We found that exercise training reduced blood pressure (BP) during fixed-load cycling at 75 W and during moderate, but not vigorous, intensity cycling exercise in adults with well-healed burn injuries. These data suggest that 6 mo of unsupervised exercise training provides some degree of cardioprotection by reducing BP responses during submaximal exercise in well-healed burn-injured adults.
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Affiliation(s)
- Joseph C Watso
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Nutrition & Integrative Physiology, Florida State University, Tallahassee, Florida
| | - Steven A Romero
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Gilbert Moralez
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Mu Huang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, Texas
- Office of Science, Medicine, and Health, American Heart Association, Dallas, Texas
| | - Matthew N Cramer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Elias Johnson
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
| | - Craig G Crandall
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas
- Department of Applied Clinical Research, School of Health Professions, University of Texas Southwestern Medical Center, Dallas, Texas
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12
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Hansen AB, Moralez G, Amin SB, Hofstätter F, Simpson LL, Gasho C, Tymko MM, Ainslie PN, Lawley JS, Hearon CM. Global REACH 2018: increased adrenergic restraint of blood flow preserves coupling of oxygen delivery and demand during exercise at high-altitude. J Physiol 2022; 600:3483-3495. [PMID: 35738560 PMCID: PMC9357095 DOI: 10.1113/jp282972] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 06/16/2022] [Indexed: 01/05/2023] Open
Abstract
Chronic exposure to hypoxia (high-altitude, HA; >4000 m) attenuates the vasodilatory response to exercise and is associated with a persistent increase in basal sympathetic nerve activity (SNA). The mechanism(s) responsible for the reduced vasodilatation and exercise hyperaemia at HA remains unknown. We hypothesized that heightened adrenergic signalling restrains skeletal muscle blood flow during handgrip exercise in lowlanders acclimatizing to HA. We tested nine adult males (n = 9) at sea-level (SL; 344 m) and following 21-28 days at HA (∼4300 m). Forearm blood flow (FBF; duplex ultrasonography), mean arterial pressure (MAP; brachial artery catheter), forearm vascular conductance (FVC; FBF/MAP), and arterial and venous blood sampling (O2 delivery ( DO2${D}_{{{\rm{O}}}_{\rm{2}}}$ ) and uptake ( V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ )) were measured at rest and during graded rhythmic handgrip exercise (5%, 15% and 25% of maximum voluntary isometric contraction; MVC) before and after local α- and β-adrenergic blockade (intra-arterial phentolamine and propranolol). HA reduced ΔFBF (25% MVC: SL: 138.3 ± 47.6 vs. HA: 113.4 ± 37.1 ml min-1 ; P = 0.022) and Δ V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ (25% MVC: SL: 20.3 ± 7.5 vs. HA: 14.3 ± 6.2 ml min-1 ; P = 0.014) during exercise. Local adrenoreceptor blockade at HA restored FBF during exercise (25% MVC: SLα-β blockade : 164.1 ± 71.7 vs. HAα-β blockade : 185.4 ± 66.6 ml min-1 ; P = 0.947) but resulted in an exaggerated relationship between DO2${D}_{{{\rm{O}}}_{\rm{2}}}$ and V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ ( DO2${D}_{{{\rm{O}}}_{\rm{2}}}$ / V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ slope: SL: 1.32; HA: slope: 1.86; P = 0.037). These results indicate that tonic adrenergic signalling restrains exercise hyperaemia in lowlanders acclimatizing to HA. The increase in adrenergic restraint is necessary to match oxygen delivery to demand and prevent over perfusion of contracting muscle at HA. KEY POINTS: In exercising skeletal muscle, local vasodilatory signalling and sympathetic vasoconstriction integrate to match oxygen delivery to demand and maintain arterial blood pressure. Exposure to chronic hypoxia (altitude, >4000 m) causes a persistent increase in sympathetic nervous system activity that is associated with impaired functional capacity and diminished vasodilatation during exercise. In healthy male lowlanders exposed to chronic hypoxia (21-28 days; ∼4300 m), local adrenoreceptor blockade (combined α- and β-adrenergic blockade) restored skeletal muscle blood flow during handgrip exercise. However, removal of tonic adrenergic restraint at high altitude caused an excessive rise in blood flow and subsequently oxygen delivery for any given metabolic demand. This investigation is the first to identify greater adrenergic restraint of blood flow during acclimatization to high altitude and provides evidence of a functional role for this adaptive response in regulating oxygen delivery and demand.
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Affiliation(s)
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, TX, USA
| | - Sachin B. Amin
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofstätter
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Lydia L. Simpson
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, University of Loma Linda, Loma Linda, California, USA
| | - Michael M. Tymko
- Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada.,Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, British Columbia, Canada
| | - Philip N. Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, British Columbia, Canada
| | - Justin S. Lawley
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher M. Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, TX, USA.,Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, TX, USA.,Correspondence: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Suite 435, Dallas, TX, 75231, USA.
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13
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Adesanya EO, Matsukawa K, Young BE, Trotter CE, Davis SL, Jarrad CP, Huang M, Smith S, Moralez G. Central Command Related Changes in Anterior Cerebral Artery Blood Velocity and Prefrontal Oxygenation at the Onset of Moderate Voluntary Hand‐Grip Exercise. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r5149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Kanji Matsukawa
- Department of Integrative PhysiologyHiroshima UniversityHiroshima
- Department of Applied Clinical ResearchHiroshima UniversityHiroshima
| | - Benjamin E. Young
- Department of Applied Clinical ResearchUT Southwestern Medical CenterDallasTX
| | - Claire E. Trotter
- Department of Applied Physiology and WellnessSouthern Methodist UniversityDallasTX
| | - Scott L. Davis
- Department of Applied Physiology and WellnessSouthern Methodist UniversityDallasTX
| | - Caitlin P. Jarrad
- Department of Applied Clinical ResearchUT Southwestern Medical CenterDallasTX
| | - Mu Huang
- Department of Applied Clinical ResearchUT Southwestern Medical CenterDallasTX
| | - Scott Smith
- Department of Applied Clinical ResearchUT Southwestern Medical CenterDallasTX
| | - Gilbert Moralez
- Department of Applied Clinical ResearchUT Southwestern Medical CenterDallasTX
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14
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Hansen AB, Amin SB, Hofstätter F, Mugele H, Simpson LL, Gasho C, Dawkins TG, Tymko MM, Ainslie PN, Villafuerte FC, Hearon CM, Lawley JS, Moralez G. Global Reach 2018: sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness. Am J Physiol Heart Circ Physiol 2022; 322:H844-H856. [PMID: 35333117 PMCID: PMC9018046 DOI: 10.1152/ajpheart.00555.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 03/14/2022] [Accepted: 03/14/2022] [Indexed: 11/22/2022]
Abstract
Andeans with chronic mountain sickness (CMS) and polycythemia have similar maximal oxygen uptakes to healthy Andeans. Therefore, this study aimed to explore potential adaptations in convective oxygen transport, with a specific focus on sympathetically mediated vasoconstriction of nonactive skeletal muscle. In Andeans with (CMS+, n = 7) and without (CMS-, n = 9) CMS, we measured components of convective oxygen delivery, hemodynamic (arterial blood pressure via intra-arterial catheter), and autonomic responses [muscle sympathetic nerve activity (MSNA)] at rest and during steady-state submaximal cycling exercise [30% and 60% peak power output (PPO) for 5 min each]. Cycling caused similar increases in heart rate, cardiac output, and oxygen delivery at both workloads between both Andean groups. However, at 60% PPO, CMS+ had a blunted reduction in Δtotal peripheral resistance (CMS-, -10.7 ± 3.8 vs. CMS+, -4.9 ± 4.1 mmHg·L-1·min-1; P = 0.012; d = 1.5) that coincided with a greater Δforearm vasoconstriction (CMS-, -0.2 ± 0.6 vs. CMS+, 1.5 ± 1.3 mmHg·mL-1·min-1; P = 0.008; d = 1.7) and a rise in Δdiastolic blood pressure (CMS-, 14.2 ± 7.2 vs. CMS+, 21.6 ± 4.2 mmHg; P = 0.023; d = 1.2) compared with CMS-. Interestingly, although MSNA burst frequency did not change at 30% or 60% of PPO in either group, at 60% Δburst incidence was attenuated in CMS+ (P = 0.028; d = 1.4). These findings indicate that in Andeans with polycythemia, light intensity exercise elicited similar cardiovascular and autonomic responses compared with CMS-. Furthermore, convective oxygen delivery is maintained during moderate-intensity exercise despite higher peripheral resistance. In addition, the elevated peripheral resistance during exercise was not mediated by greater sympathetic neural outflow, thus other neural and/or nonneural factors are perhaps involved.NEW & NOTEWORTHY During submaximal exercise, convective oxygen transport is maintained in Andeans suffering from polycythemia. Light intensity exercise elicited similar cardiovascular and autonomic responses compared with healthy Andeans. However, during moderate-intensity exercise, we observed a blunted reduction in total peripheral resistance, which cannot be ascribed to an exaggerated increase in muscle sympathetic nerve activity, indicating possible contributions from other neural and/or nonneural mechanisms.
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Affiliation(s)
- Alexander B Hansen
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Sachin B Amin
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofstätter
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Hendrik Mugele
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Lydia L Simpson
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, Department of Medicine, University of Loma Linda, Loma Linda, California
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Michael M Tymko
- Physical Activity and Diabetes Laboratory, Faculty of Kinesiology and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas
| | - Justin S Lawley
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
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15
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Watso JC, Romero SA, Moralez G, Huang M, Cramer MN, Jaffery MF, Balmain BN, Wilhite DP, Babb TG, Crandall CG. Adults with well-healed burn injuries have lower pulmonary function values decades after injury. Physiol Rep 2022; 10:e15264. [PMID: 35581737 PMCID: PMC9114657 DOI: 10.14814/phy2.15264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 03/25/2022] [Indexed: 06/15/2023] Open
Abstract
Sub-acute (e.g., inhalation injury) and/or acute insults sustained during a severe burn injury impairs pulmonary function. However, previous work has not fully characterized pulmonary function in adults with well-healed burn injuries decades after an injury. Therefore, we tested the hypothesis that adults with well-healed burn injuries have lower pulmonary function years after recovery. Our cohort of adults with well-healed burn-injuries (n = 41) had a lower forced expiratory volume in one second (Burn: 93 ± 16 vs. Control: 103 ± 10%predicted, mean ± SD; d = 0.60, p = 0.04), lower maximal voluntary ventilation (Burn: 84 [71-97] vs. Control: 105 [94-122] %predicted, median [IQR]; d = 0.84, p < 0.01), and a higher specific airway resistance (Burn: 235 ± 80 vs. Control: 179 ± 40%predicted, mean ± SD; d = 0.66, p = 0.02) than non-burned control participants (n = 12). No variables were meaningfully influenced by having a previous inhalation injury (d ≤ 0.44, p ≥ 0.19; 13 of 41 had an inhalation injury), the size of the body surface area burned (R2 ≤ 0.06, p ≥ 0.15; range of 15%-88% body surface area burned), or the time since the burn injury (R2 ≤ 0.04, p ≥ 0.22; range of 2-50 years post-injury). These data suggest that adults with well-healed burn injuries have lower pulmonary function decades after injury. Therefore, future research should examine rehabilitation strategies that could improve pulmonary function among adults with well-healed burn injuries.
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Affiliation(s)
- Joseph C. Watso
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- Department of Applied Clinical ResearchSchool of Health ProfessionsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Steven A. Romero
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- Department of Physiology & AnatomyUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Gilbert Moralez
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- Department of Applied Clinical ResearchSchool of Health ProfessionsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Mu Huang
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
- Department of Applied Clinical ResearchSchool of Health ProfessionsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Matthew N. Cramer
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
| | - Manall F. Jaffery
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
| | - Bryce N. Balmain
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
| | - Daniel P. Wilhite
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
| | - Tony G. Babb
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
| | - Craig G. Crandall
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasDallasTexasUSA
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16
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Hansen AB, Moralez G, Amin SB, Simspon LL, Hofstaetter F, Anholm JD, Gasho C, Stembridge M, Dawkins TG, Tymko MM, Ainslie PN, Villafuerte F, Romero SA, Hearon CM, Lawley JS. Global REACH 2018: the adaptive phenotype to life with chronic mountain sickness and polycythaemia. J Physiol 2021; 599:4021-4044. [PMID: 34245004 DOI: 10.1113/jp281730] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/18/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Humans suffering from polycythaemia undergo multiple circulatory adaptations including changes in blood rheology and structural and functional vascular adaptations to maintain normal blood pressure and vascular shear stresses, despite high blood viscosity. During exercise, several circulatory adaptations are observed, especially involving adrenergic and non-adrenergic mechanisms within non-active and active skeletal muscle to maintain exercise capacity, which is not observed in animal models. Despite profound circulatory stress, i.e. polycythaemia, several adaptations can occur to maintain exercise capacity, therefore making early identification of the disease difficult without overt symptomology. Pharmacological treatment of the background heightened sympathetic activity may impair the adaptive sympathetic response needed to match local oxygen delivery to active skeletal muscle oxygen demand and therefore inadvertently impair exercise capacity. ABSTRACT Excessive haematocrit and blood viscosity can increase blood pressure, cardiac work and reduce aerobic capacity. However, past clinical investigations have demonstrated that certain human high-altitude populations suffering from excessive erythrocytosis, Andeans with chronic mountain sickness, appear to have phenotypically adapted to life with polycythaemia, as their exercise capacity is comparable to healthy Andeans and even with sea-level inhabitants residing at high altitude. By studying this unique population, which has adapted through natural selection, this study aimed to describe how humans can adapt to life with polycythaemia. Experimental studies included Andeans with (n = 19) and without (n = 17) chronic mountain sickness, documenting exercise capacity and characterizing the transport of oxygen through blood rheology, including haemoglobin mass, blood and plasma volume and blood viscosity, cardiac output, blood pressure and changes in total and local vascular resistances through pharmacological dissection of α-adrenergic signalling pathways within non-active and active skeletal muscle. At rest, Andeans with chronic mountain sickness had a substantial plasma volume contraction, which alongside a higher red blood cell volume, caused an increase in blood viscosity yet similar total blood volume. Moreover, both morphological and functional alterations in the periphery normalized vascular shear stress and blood pressure despite high sympathetic nerve activity. During exercise, blood pressure, cardiac work and global oxygen delivery increased similar to healthy Andeans but were sustained by modifications in both non-active and active skeletal muscle vascular function. These findings highlight widespread physiological adaptations that can occur in response to polycythaemia, which allow the maintenance of exercise capacity.
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Affiliation(s)
- Alexander B Hansen
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Southwestern Medical Center, Dallas, Texas, USA
| | - Sachin B Amin
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - Lydia L Simspon
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofstaetter
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - James D Anholm
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University, Loma Linda, California, USA
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University, Loma Linda, California, USA
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Michael M Tymko
- Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Alberta, Canada.,Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Francisco Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Steven A Romero
- University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Southwestern Medical Center, Dallas, Texas, USA.,Institute of Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
| | - Justin S Lawley
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
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17
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Hansen A, Moralez G, Amin S, Hofstätter F, Gasho C, Tymko M, Ainslie P, Hearon C, Lawley J. Global REACH 2018: heightened α‐adrenergic signaling restrains blood flow to precisely match oxygen delivery and demand during handgrip exercise in Andeans with polycythemia. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Gilbert Moralez
- Department of Applied Clinical ResearchUniversity of Texas Southwestern Medical CenterDallasTX
| | - Sachin Amin
- Sport ScienceUniversity of InnsbruckInnsbruck
| | | | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical CareUniversity of Loma LidaLoma LidaCA
| | - Michael Tymko
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonAB
| | - Philip Ainslie
- School of Health and Exercise SciencesUniversity of British Columbia ‐ OkanaganKelownaBC
| | - Christopher Hearon
- Applied Clinical ResearchUniversity of Texas Southwestern Medical CenterDallasTX
- Cardiovascular PhysiologyUniversity of Texas Southwestern Medical CenterDallasTX
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18
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Cramer MN, Huang M, Fischer M, Moralez G, Crandall CG. Thermoregulatory Responses with Size-matched Simulated Torso or Limb Skin Grafts. Med Sci Sports Exerc 2021; 53:2190-2195. [PMID: 33935232 PMCID: PMC8440327 DOI: 10.1249/mss.0000000000002694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Skin grafting following a burn injury attenuates/abolishes sweat production within grafted areas. It is presently unknown whether the thermoregulatory consequences of skin grafting depend on anatomical location. PURPOSE To test the hypothesis that a simulated burn injury on the torso will be no more or less detrimental to core temperature control than on the limbs during uncompensable exercise-heat stress. METHODS Nine non-burned individuals (7 males, 2 females) completed the protocol. On separate occasions, burn injuries of identical surface area (0.45 ± 0.08 m2 or 24.4% ± 4.4% of total body surface area) were simulated on the torso or the arms/legs using an absorbent, vapor-impermeable material that impedes sweat evaporation in those regions. Participants performed 60 min of treadmill walking at 5.3 km·h-1 and a 4.1% ± 0.8% grade, targeting 6 W·kg-1 of metabolic heat production in 40.1°C ± 0.2°C and 19.6% ± 0.6% relative humidity conditions. Rectal temperature, heart rate, and perceptual responses were measured. RESULTS Rectal temperature increased to a similar extent with simulated injuries on the torso and limbs (condition-by-time interaction: P = 0.86), with a final rectal temperature 0.9 ± 0.3°C above baseline in both conditions. No differences in heart rate, perceived exertion, or thermal sensation were observed between conditions (condition-by-time interactions: P ≥ 0.50). CONCLUSION During uncompensable exercise-heat stress, sized-matched simulated burn injuries on the torso or limbs evoke comparable core temperature, heart rate, and perceptual responses, suggesting that the risk of exertional heat illness in such environmental conditions is independent of injury location.
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Affiliation(s)
- Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA Department of Nutrition, Exercise and Sports, University of Copenhagen and Department of Anaesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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19
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Belval LN, Cramer MN, Moralez G, Huang MU, Cimino FA, Watso JC, Crandall CG. Interaction of Exercise Intensity and Simulated Burn Injury Size on Thermoregulation. Med Sci Sports Exerc 2021; 53:367-374. [PMID: 32826639 PMCID: PMC7995740 DOI: 10.1249/mss.0000000000002480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study aimed to test the hypothesis that the elevation in internal body temperature during exercise in a hot environment is influenced by the combination of exercise intensity and BSA burned. METHODS Ten healthy participants (8 males, 2 females; 32 ± 9 yr; 75.3 ± 11.7 kg) completed eight exercise trials on a cycle ergometer, each with different combinations of metabolic heat productions (low, 4 W·kg-1; moderate, 6 W·kg-1) and simulated BSA burn in a hot environmental chamber (39.9°C ± 0.3°C, 20.1% ± 1.5% RH). Burns were simulated by covering 0%, 20%, 40%, or 60% of participants' BSA with a highly absorbent, vapor-impermeable material. Gastrointestinal temperature (TGI) was recorded, with the primary analysis being the increase in TGI after 60 min of exercise. RESULTS We identified an interaction effect for the increase in TGI (P < 0.01), suggesting TGI was influenced by both intensity and simulated burn BSA. Regardless of the percentage BSA burn simulated, the increase in TGI was similar across low-intensity trials (0.70°C ± 0.26°C, P > 0.11 for all). However, during moderate-intensity exercise, the increase in TGI was greater for the 60% (1.78°C ± 0.38°C, P < 0.01) and 40% BSA coverage trials (1.33°C ± 0.44°C, P = 0.04), relative to 0% (0.82°C ± 0.36°C). There were no differences in TGI responses between 0% and 20% trials. CONCLUSION These data suggest that exercise intensity influences the relationship between burn injury size and thermoregulatory responses in a hot environment.
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Affiliation(s)
- Luke N Belval
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | - Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | | | | | - Frank A Cimino
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | - Joseph C Watso
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
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20
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Huang M, Watso JC, Moralez G, Cramer MN, Hendrix JM, Yoo JK, Badrov MB, Fu Q, Hinojosa-Laborde C, Crandall CG. Low-dose ketamine affects blood pressure, but not muscle sympathetic nerve activity, during progressive central hypovolemia without altering tolerance. J Physiol 2020; 598:5661-5672. [PMID: 33084081 DOI: 10.1113/jp280491] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/02/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Haemorrhage is the leading cause of battlefield and civilian trauma deaths. Given that a haemorrhagic injury on the battlefield is almost always associated with pain, it is paramount that the administered pain medication does not disrupt the physiological mechanisms that are beneficial in defending against the haemorrhagic insult. Current guidelines from the US Army's Committee on Tactical Combat Casualty Care (CoTCCC) for the selection of pain medications administered to a haemorrhaging soldier are based upon limited scientific evidence, with the clear majority of supporting studies being conducted on anaesthetized animals. Specifically, the influence of low-dose ketamine, one of three analgesics employed in the pre-hospital setting by the US Army, on haemorrhagic tolerance in humans is unknown. For the first time in conscious males and females, the findings of the present study demonstrate that the administration of an analgesic dose of ketamine does not compromise tolerance to a simulated haemorrhagic insult. Increases in muscle sympathetic nerve activity during progressive lower-body negative pressure were not different between trials. Despite the lack of differences for muscle sympathetic nerve activity responses, mean blood pressure and heart rate were higher during moderate hypovolemia after ketamine vs. placebo administration. ABSTRACT Haemorrhage is the leading cause of battlefield and civilian trauma deaths. For a haemorrhaging soldier, there are several pain medications (e.g. ketamine) recommended for use in the prehospital, field setting. However, the data to support these recommendations are primarily limited to studies in animals. Therefore, it is unknown whether ketamine adversely affects physiological mechanisms responsible for maintenance of arterial blood pressure (BP) during haemorrhage in humans. In humans, ketamine has been demonstrated to raise resting BP, although it has not been studied with the concomitant central hypovolemia that occurs during haemorrhage. Thus, the present study aimed to test the hypothesis that ketamine does not impair haemorrhagic tolerance in humans. Thirty volunteers (15 females) participated in this double-blinded, randomized, placebo-controlled trial. A pre-syncopal limited progressive lower-body negative pressure (LBNP; a validated model for simulating haemorrhage) test was conducted following the administration of ketamine (20 mg) or placebo (saline). Tolerance was quantified as a cumulative stress index and compared between trials using a paired, two-tailed t test. We compared muscle sympathetic nerve activity (MSNA; microneurography), beat-to-beat BP (photoplethysmography) and heart rate (electrocardiogram) responses during the LBNP test using a mixed effects model (time [LBNP stage] × drug). Tolerance to the LBNP test was not different between trials (Ketamine: 635 ± 391 vs. Placebo: 652 ± 360 mmHg‧min, p = 0.77). Increases in MSNA burst frequency (time: P < 0.01, trial: p = 0.27, interaction: p = 0.39) during LBNP stages were no different between trials. Despite the lack of differences for MSNA responses, mean BP (time: P < 0.01, trial: P < 0.01, interaction: p = 0.01) and heart rate (time: P < 0.01, trial: P < 0.01, interaction: P < 0.01) were higher during moderate hypovolemia after ketamine vs. placebo administration (P < 0.05 for all, post hoc), but not at the end of LBNP. These data, which are the first to be obtained in conscious humans, demonstrate that the administration of low-dose ketamine does not impair tolerance to simulated haemorrhage or mechanisms responsible for maintenance of BP.
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Affiliation(s)
- Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joseph C Watso
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Present address: Defense Research and Development Canada-Toronto Research Centre, Toronto, ON, Canada
| | - Joseph M Hendrix
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeung-Ki Yoo
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Mark B Badrov
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Present address: University Health Network and Sinai Health System Division of Cardiology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
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21
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Watso JC, Huang M, Moralez G, Cramer MN, Hendrix JM, Cimino FA, Belval LN, Hinojosa‐Laborde C, Crandall CG. Low dose ketamine reduces pain perception and blood pressure, but not muscle sympathetic nerve activity, responses during a cold pressor test. J Physiol 2020; 599:67-81. [DOI: 10.1113/jp280706] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/01/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Joseph C. Watso
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
| | - Mu Huang
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
- Department of Applied Clinical Research University of Texas Southwestern Medical Center Dallas TX USA
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
- Department of Applied Clinical Research University of Texas Southwestern Medical Center Dallas TX USA
| | - Matthew N. Cramer
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
| | - Joseph M. Hendrix
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
- Department of Anesthesiology University of Texas Southwestern Medical Center Dallas TX USA
| | - Frank A. Cimino
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
| | - Luke N. Belval
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
| | | | - Craig G. Crandall
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center Dallas TX USA
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22
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Romero SA, Moralez G, Jaffery MF, Huang MU, Engelland RE, Cramer MN, Crandall CG. Exercise Training Improves Microvascular Function in Burn Injury Survivors. Med Sci Sports Exerc 2020; 52:2430-2436. [PMID: 33064412 DOI: 10.1249/mss.0000000000002379] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Vasodilator function is impaired in individuals with well-healed burn injuries; however, therapeutic interventions that lessen or reverse this maladaptation are lacking. The purpose of this study was to test the hypothesis that a 6-month community-based exercise training program would increase microvascular dilator function in individuals with well-healed burn injuries, irrespective of the magnitude of the injured body surface area. Further, we hypothesize that macrovascular dilator function would remain unchanged posttraining. METHODS Microvascular function (forearm reactive hyperemia), macrovascular function (brachial artery flow-mediated dilation), and the maximal vasodilatory response after ischemic handgrip exercise (an estimate of microvascular remodeling) were assessed before and after exercise training in nonburned control subjects (n = 11) and individuals with burn injuries covering a moderate body surface area (26% ± 7%; n = 13) and a high body surface area (59% ± 15%; n = 19). RESULTS Peak vascular conductance and area under the curve during postocclusive reactive hyperemia increased from pretraining to posttraining in control and burn injury groups (both P < 0.05), the magnitude of which did not differ between groups (both P = 0.6). Likewise, the maximal vasodilatory response after ischemic handgrip exercise increased in all groups after exercise training (P < 0.05). Macrovascular dilator function did not differ across time or between groups (P = 0.8). CONCLUSIONS These data suggest that a community-based exercise training program improves microvascular function in individuals with well-healed burn injuries, which may be due in part to vascular remodeling.
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Affiliation(s)
| | - Gilbert Moralez
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - Manall F Jaffery
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - M U Huang
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | | | - Matthew N Cramer
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
| | - Craig G Crandall
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX
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23
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Cramer MN, Moralez G, Huang MU, Kouda K, Poh PYS, Crandall CG. Exercise Core Temperature Response with a Simulated Burn Injury: Effect of Body Size. Med Sci Sports Exerc 2020; 52:705-711. [PMID: 31524829 DOI: 10.1249/mss.0000000000002160] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although the severity of a burn injury is often associated with the percentage of total body surface area burned (%TBSA), the thermoregulatory consequences of a given %TBSA injury do not account for the interactive effects of body morphology and metabolic heat production (Hprod). PURPOSE Using a simulated burn injury model to mimic the detrimental effect of a 40% TBSA injury on whole-body evaporative heat dissipation, core temperature response to exercise in physiologically uncompensable conditions between morphologically disparate groups were examined at (i) an absolute Hprod (W), and (ii) a mass-specific Hprod (W·kg). METHODS Healthy, young, nonburned individuals of small (SM, n = 11) or large (LG, n = 11) body size cycled for 60 min at 500 W or 5.3 W·kg of Hprod in 39°C and 20% relative humidity conditions. A 40% burn injury was simulated by affixing a highly absorbent, vapor-impermeable material across the torso (20% TBSA), arms (10% TBSA), and legs (10% TBSA) to impede evaporative heat loss in those regions. RESULTS Although the elevation in core temperature was greater in SM compared with LG at an Hprod of 500 W (SM, 1.69°C ± 0.26°C; LG, 1.05°C ± 0.26°C; P < 0.01), elevations in core temperature were not different at an Hprod of 5.3 W·kg between groups (SM, 0.99°C ± 0.32°C; LG, 1.05°C ± 0.26°C; P = 0.66). CONCLUSIONS These data suggest that among individuals with a 40% TBSA burn injury, a smaller body size leads to exacerbated elevations in core temperature during physical activities eliciting the same absolute Hprod (non-weight-bearing tasks) but not activities eliciting the same mass-specific Hprod (weight-bearing tasks).
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Affiliation(s)
- Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | | | | | | | | | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
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24
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Cramer MN, Moralez G, Huang MU, Kouda K, Poh PYS, Crandall CG. Exercise Thermoregulation with a Simulated Burn Injury: Impact of Air Temperature. Med Sci Sports Exerc 2020; 52:712-719. [PMID: 31609298 DOI: 10.1249/mss.0000000000002184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The U.S. Army's Standards of Medical Fitness (AR 40-501) states: "Prior burn injury (to include donor sites) involving a total body surface area of 40% or more does not meet the standard." However, the standard does not account for the interactive effect of burn injury size and air temperature on exercise thermoregulation. PURPOSE To evaluate whether the detrimental effect of a simulated burn injury on exercise thermoregulation is dependent on air temperature. METHODS On eight occasions, nine males cycled for 60 min at a fixed metabolic heat production (6 W·kg) in air temperatures of 40°C or 25°C with simulated burn injuries of 0% (Control), 20%, 40%, or 60% of total body surface area (TBSA). Burn injuries were simulated by covering the skin with an absorbent, vapor-impermeable material to impede evaporation from the covered areas. Core temperature was measured in the gastrointestinal tract via telemetric pill. RESULTS In 40°C conditions, greater elevations in core temperature were observed with 40% and 60% TBSA simulated burn injuries versus Control (P < 0.01). However, at 25°C, core temperature responses were not different versus Control with 20%, 40%, and 60% TBSA simulated injuries (P = 0.97). The elevation in core temperature at the end of exercise was greater in the 40°C environment with 20%, 40%, and 60% TBSA simulated burn injuries (P ≤ 0.04). CONCLUSIONS Simulated burn injuries ≥20% TBSA exacerbate core temperature responses in hot, but not temperate, air temperatures. These findings suggest that the U.S. Army's standard for inclusion of burned soldiers is appropriate for hot conditions, but could lead to the needless discharge of soldiers who could safely perform their duties in cooler training/operational settings.
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Affiliation(s)
- Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | | | | | | | | | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
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25
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Cramer MN, Hieda M, Huang M, Moralez G, Crandall CG. Dietary nitrate supplementation does not influence thermoregulatory or cardiovascular strain in older individuals during severe ambient heat stress. Exp Physiol 2020; 105:1730-1741. [PMID: 32816341 DOI: 10.1113/ep088834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/17/2020] [Indexed: 12/16/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does dietary nitrate supplementation with beetroot juice attenuate thermoregulatory and cardiovascular strain in older adults during severe heat stress? What is the main finding and its importance? A 7-day nitrate supplementation regimen lowered resting mean arterial pressure in thermoneutral conditions. During heat stress, core and mean skin temperatures, vasodilatory responses, sweat loss, heart rate and left ventricular function were unchanged, and mean arterial pressure was only transiently reduced, post-supplementation. These data suggest nitrate supplementation with beetroot juice does not mitigate thermoregulatory or cardiovascular strain in heat-stressed older individuals. ABSTRACT This study tested the hypothesis that dietary nitrate supplementation with concentrated beetroot juice attenuates thermoregulatory and cardiovascular strain in older individuals during environmental heat stress. Nine healthy older individuals (six females, three males; aged 67 ± 5 years) were exposed to 42.5 ± 0.1°C and 34.0 ± 0.5% relative humidity conditions for 120 min before (CON) and after 7 days of dietary nitrate supplementation with concentrated beetroot juice (BRJ; 280 ml, ∼16.8 mmol of nitrate daily). Core and skin temperatures, body mass changes (indicative of whole-body sweat loss), skin blood flow and cutaneous vascular conductance, forearm blood flow and vascular conductance, heart rate, arterial blood pressures and indices of cardiac function were measured. The 7-day beetroot juice regimen increased plasma nitrate/nitrite levels from 27.4 ± 15.2 to 477.0 ± 102.5 μmol l-1 (P < 0.01) and lowered resting mean arterial pressure from 90 ± 7 to 83 ± 10 mmHg at baseline under thermoneutral conditions (P = 0.02). However, during subsequent heat stress, no differences in core and skin temperatures, skin blood flow and vascular conductance, forearm blood flow and vascular conductance, whole-body sweat loss, heart rate, and echocardiographic indices of systolic function and diastolic filling were evident following nitrate supplementation (all P > 0.05). Mean arterial pressure was lower in BRJ vs. CON during heat stress (treatment-by-time interaction: P = 0.02). Overall, these findings suggest that dietary nitrate supplementation with concentrated beetroot juice does not attenuate thermoregulatory or cardiovascular strain in older individuals exposed to severe ambient heat stress.
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Affiliation(s)
- Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michinari Hieda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA.,School of Medicine, Kyushu University, Fukuoka, Japan
| | - Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA.,Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA.,Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX, USA
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Huang M, Moralez G, Romero SA, Jaffery MF, Cramer MN, Petric JK, Nabasny AD, Crandall CG. The benefits of an unsupervised exercise program in persons with well-healed burn injuries within the International Classification of Functioning, Disability and Health (ICF). Burns 2020; 46:1280-1288. [PMID: 32660830 DOI: 10.1016/j.burns.2020.06.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 10/23/2022]
Abstract
Vast improvements in the survival rates following burn injuries has led to a greater number of patients living with a wide range of long-term impairments, activity limitations, and participation constraints. Therefore, long-term care is critical in this clinical population and necessitates appropriate rehabilitation strategies to maximize an individual's overall health. The purpose of this study was to test the hypothesis that the extent to which outcomes within the International Classification of Functioning, Disability, and Health (ICF) framework are improved following 6 months of unsupervised exercise training is influenced by the severity of a burn injury (i.e., percent body surface area injured). Outcome variables representing the dimensions of the ICF, body functions & structure, activity, and participation, were collected pre- and post- 6 months of exercise training in three groups of participants: non-injured control subjects (N = 11), subjects with moderate-level well-healed burn injuries (N = 13, 26 ± 6% body surface area burned), and subjects with high-level well-healed burn injuries (N = 20, 58 ± 15% body surface area burned). Exercise training improved lower extremity strength (changes in peak torque/kg body mass at 90 degrees/sec flexion: 30 ± 5% and extension: 36 ± 4%, p < 0.05) and functional activities (changes in sit to stand: -9 ± 4% and ascend stairs: -4 ± 1%; p < 0.05) in all groups. For outcome variables representing ICF levels of body functions & structure and activity, there were no differences at baseline or improvements made between the groups after training. That said, with the exception of the domain of functional activity (reported 17 ± 34% improvement in the high-level burn cohort, p < 0.05), no changes were revealed in the participation level of ICF indexed by health-related quality of life questionnaires. These findings support the utilization of a 6-month unsupervised exercise training program in the long-term rehabilitation of individuals with burn injuries; that is, improvements in body functions & structure and activity can be achieved with an exercise regimen regardless of the severity of burn injury.
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Affiliation(s)
- Mu Huang
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, USA; University of Texas Southwestern Medical Center School of Health Professions, Dallas, TX, USA
| | - Gilbert Moralez
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, USA; University of Texas Southwestern Medical Center School of Health Professions, Dallas, TX, USA
| | - Steven A Romero
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, USA; University of North Texas Health Science Center, Ft. Worth, TX, USA
| | - Manall F Jaffery
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, USA
| | - Matthew N Cramer
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, USA
| | - Jan Karel Petric
- University of Texas Southwestern Medical Center School of Health Professions, Dallas, TX, USA
| | - Andrew D Nabasny
- University of Texas Southwestern Medical Center School of Health Professions, Dallas, TX, USA
| | - Craig G Crandall
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, USA.
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Watso JC, Huang M, Moralez G, Cramer MN, Hendrix JM, Cimino FA, Belval LN, Hinojosa-Laborde C, Fu Q, Crandall CG. Blood Pressure Responses During A Cold Pressor Test Following Ketamine Or Fentanyl Analgesic Administration. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000679984.66784.f9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Huang M, Watso JC, Moralez G, Cramer MN, Hendrix JM, Fischer M, Belval LN, Cimino FA, Hinojosa-Laborde C, Crandall CG. Analgesics In The Pre-hospital Setting: Fentanyl Does Not Alter Tolerance To Simulated Hemorrhage In Humans. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000679988.97591.6d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Samuel TJ, Nelson MD, Nasirian A, Jaffery M, Moralez G, Romero SA, Cramer MN, Huang M, Kouda K, Hieda M, Sarma S, Crandall CG. Cardiac Structure and Function in Well-Healed Burn Survivors. J Burn Care Res 2020; 40:235-241. [PMID: 30649454 DOI: 10.1093/jbcr/irz008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Long-term burn survivors have reduced aerobic capacity, placing them at increased risk for cardiovascular disease, morbidity, and mortality. However, the exact mechanism contributing to a reduced aerobic capacity remains incompletely understood, but may be related to adverse cardiovascular remodeling. Therefore, it was hypothesized that well-healed burn survivors would exhibit adverse left ventricular (LV) remodeling and impaired LV function. To test this hypothesis, 22 well-healed moderately burned individuals (age: 41 ± 14 years; BMI: 27.7 ± 5.4 kg/m2; male/female: 12/10; extent of burn: 37 ± 12 %BSA), 11 well-healed severely burned individuals (age: 43 ± 12 years; BMI: 29.5 ± 5.8 kg/m2; male/female: 8/3; extent of burn: 73 ± 11 %BSA), and 12 healthy, age-matched controls (age: 34 ± 9 years; BMI: 28.6 ± 5.2 kg/m2; male/female: 5/7) were enrolled in the study. All subjects were sedentary, performing less than 30 minutes of aerobic exercise per day, 3 days per week. LV morphology and function were assessed via cardiac magnetic resonance imaging. In contrast to the hypothesis, neither the presence nor severity of burn injury adversely affected LV morphology or function, when compared with equally sedentary nonburned controls. However, of note, LV mass of all three groups was in the lowest 5th percentile compared with normative values. Finally, group differences in LV morphology were largely explained by differences in aerobic capacity. Taken together, these data suggest a prior burn injury itself does not result in pathological remodeling of the LV and support a role for aerobic exercise training to improve cardiac function.
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Affiliation(s)
- T Jake Samuel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Michael D Nelson
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Aida Nasirian
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Manall Jaffery
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
| | - Steven A Romero
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas.,Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
| | - Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
| | - Ken Kouda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
| | - Michinari Hieda
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Department of Internal Medicine, University of Texas Southwestern, Dallas, Texas
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Hansen AB, Moralez G, Romero SA, Gasho C, Tymko MM, Ainslie PN, Hofstätter F, Rainer SL, Lawley JS, Hearon CM. Mechanisms of sympathetic restraint in human skeletal muscle during exercise: role of α-adrenergic and nonadrenergic mechanisms. Am J Physiol Heart Circ Physiol 2020; 319:H192-H202. [PMID: 32502375 DOI: 10.1152/ajpheart.00208.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sympathetic vasoconstriction is mediated by α-adrenergic receptors under resting conditions. During exercise, increased sympathetic nerve activity (SNA) is directed to inactive and active skeletal muscle; however, it is unclear what mechanism(s) are responsible for vasoconstriction during large muscle mass exercise in humans. The aim of this study was to determine the contribution of α-adrenergic receptors to sympathetic restraint of inactive skeletal muscle and active skeletal muscle during cycle exercise in healthy humans. In ten male participants (18-35 yr), mean arterial pressure (intra-arterial catheter) and forearm vascular resistance (FVR) and conductance (FVC) were assessed during cycle exercise (60% total peak workload) alone and during combined cycle exercise + handgrip exercise (HGE) before and after intra-arterial blockade of α- and β-adrenoreceptors via phentolamine and propranolol, respectively. Cycle exercise caused vasoconstriction in the inactive forearm that was attenuated ~80% with adrenoreceptor blockade (%ΔFVR, +81.7 ± 84.6 vs. +9.7 ± 30.7%; P = 0.05). When HGE was performed during cycle exercise, the vasodilatory response to HGE was restrained by ~40% (ΔFVC HGE, +139.3 ± 67.0 vs. cycle exercise: +81.9 ± 66.3 ml·min-1·100 mmHg-1; P = 0.03); however, the restraint of active skeletal muscle blood flow was not due to α-adrenergic signaling. These findings highlight that α-adrenergic receptors are the primary, but not the exclusive mechanism by which sympathetic vasoconstriction occurs in inactive and active skeletal muscle during exercise. Metabolic activity or higher sympathetic firing frequencies may alter the contribution of α-adrenergic receptors to sympathetic vasoconstriction. Finally, nonadrenergic vasoconstrictor mechanisms may be important for understanding the regulation of blood flow during exercise.NEW & NOTEWORTHY Sympathetic restraint of vascular conductance to inactive skeletal muscle is critical to maintain blood pressure during moderate- to high-intensity whole body exercise. This investigation shows that cycle exercise-induced restraint of inactive skeletal muscle vascular conductance occurs primarily because of activation of α-adrenergic receptors. Furthermore, exercise-induced vasoconstriction restrains the subsequent vasodilatory response to hand-grip exercise; however, the restraint of active skeletal muscle vasodilation was in part due to nonadrenergic mechanisms. We conclude that α-adrenergic receptors are the primary but not exclusive mechanism by which sympathetic vasoconstriction restrains blood flow in humans during whole body exercise and that metabolic activity modulates the contribution of α-adrenergic receptors.
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Affiliation(s)
- Alexander B Hansen
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Steven A Romero
- University of North Texas Health Science Center, Fort Worth, Texas
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, Department of Medicine, University of Loma Lida, Loma Lida, California
| | - Michael M Tymko
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada.,Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Florian Hofstätter
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Simon L Rainer
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Justin S Lawley
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas.,University of Texas Southwestern Medical Center, Dallas, Texas
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Tymko MM, Lawley JS, Ainslie PN, Hansen AB, Hofstaetter F, Rainer S, Amin S, Moralez G, Gasho C, Vizcardo-Galindo G, Bermudez D, Villafuerte FC, Hearon CM. Global Reach 2018 Heightened α-Adrenergic Signaling Impairs Endothelial Function During Chronic Exposure to Hypobaric Hypoxia. Circ Res 2020; 127:e1-e13. [PMID: 32268833 DOI: 10.1161/circresaha.119.316053] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RATIONALE Chronic exposure to hypoxia is associated with elevated sympathetic nervous activity and reduced vascular function in lowlanders, and Andean highlanders suffering from excessive erythrocytosis (EE); however, the mechanistic link between chronically elevated sympathetic nervous activity and hypoxia-induced vascular dysfunction has not been determined. OBJECTIVE To determine the impact of heightened sympathetic nervous activity on resistance artery endothelial-dependent dilation (EDD), and endothelial-independent dilation, in lowlanders and Andean highlanders with and without EE. METHODS AND RESULTS We tested healthy lowlanders (n=9) at sea level (344 m) and following 14 to 21 days at high altitude (4300 m), and permanent Andean highlanders with (n=6) and without (n=9) EE at high altitude. Vascular function was assessed using intraarterial infusions (3 progressive doses) of acetylcholine (ACh; EDD) and sodium nitroprusside (endothelial-independent dilation) before and after local α+β adrenergic receptor blockade (phentolamine and propranolol). Intraarterial blood pressure, heart rate, and simultaneous brachial artery diameter and blood velocity were recorded at rest and during drug infusion. Changes in forearm vascular conductance were calculated. The main findings were (1) chronic hypoxia reduced EDD in lowlanders (changes in forearm vascular conductance from sea level: ACh1: -52.7±19.6%, ACh2: -25.4±38.7%, ACh3: -35.1±34.7%, all P≤0.02); and in Andeans with EE compared with non-EE (changes in forearm vascular conductance at ACh3: -36.4%, P=0.007). Adrenergic blockade fully restored EDD in lowlanders at high altitude, and normalized EDD between EE and non-EE Andeans. (2) Chronic hypoxia had no effect on endothelial-independent dilation in lowlanders, and no differences were detected between EE and non-EE Andeans; however, EID was increased in the non-EE Andeans after adrenergic blockade (P=0.012), but this effect was not observed in the EE Andeans. CONCLUSIONS These data indicate that chronic hypoxia reduces EDD via heightened α-adrenergic signaling in lowlanders and in Andeans with EE. These vascular mechanisms have important implications for understanding the physiological consequences of acute and chronic high altitude adaptation.
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Affiliation(s)
- Michael M Tymko
- From the Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada (M.M.T., P.N.A.).,Neurovascular Health Lab, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Canada (M.M.T.)
| | - Justin S Lawley
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Philip N Ainslie
- From the Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada (M.M.T., P.N.A.)
| | | | | | - Simon Rainer
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Sachin Amin
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX (G.M.)
| | | | | | | | | | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas (C.M.H.).,Department of Internal Medicine, University of Texas Southwestern Medical Center (C.M.H.)
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Moralez G, Hansen AB, Amin SB, Hofstatter F, Tymko MM, Ainslie PN, Hearon CM, Lawley JS. Muscle sympathetic nerve activity in altitude acclimatized lowlanders during leg cycling exercise. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.09846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | | | - Christopher M. Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center
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Huang M, Cramer MN, Moralez G, Crandall CG. Use of a Water‐soaked Garment, with and without an Electric Fan, to Mitigate Thermal Strain in Older Individuals under Heat Wave Conditions. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.02438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mu Huang
- University of Texas Southwestern Medical Center
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical Center
| | - Matthew N. Cramer
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical Center
| | | | - Craig G. Crandall
- Institute for Exercise and Environmental Medicine Texas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical Center
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34
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Cramer MN, Huang M, Moralez G, Crandall CG. Keeping older individuals cool in hot and moderately humid conditions: wetted clothing with and without an electric fan. J Appl Physiol (1985) 2020; 128:604-611. [PMID: 32027545 DOI: 10.1152/japplphysiol.00786.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The present study evaluated whether wearing a water-soaked t-shirt, with or without electric fan use, mitigates thermal and cardiovascular strain in older individuals exposed to hot and moderately humid conditions. Nine healthy older individuals (68 ± 4 yr; five women) completed three 120-min heat exposures (42.4 ± 0.2°C, 34.2 ± 0.9% relative humidity) on separate days while wearing a dry t-shirt (CON), a t-shirt soaked with 500 ml of tap water (WET), or a t-shirt soaked with 500 ml of tap water while facing an electric fan (2.4 ± 0.4 m/s; WET+FAN). Measurements included core and skin temperatures, evaporative mass losses, heart rate, and blood pressure. In the WET condition, elevations in core temperature were attenuated compared with DRY from 30 to 120 min and compared with WET+FAN from 30 to 90 min (P < 0.05). Evaporative mass losses (inclusive of sweat and water losses from the shirt) were greatest in WET+FAN, followed by WET, and then DRY (P < 0.01). Sweat losses were lowest in WET, followed by DRY, and then WET+FAN (P < 0.01). Heart rate was lower only at 60 min in WET versus DRY (P = 0.01). No differences in mean arterial pressure were observed (P = 0.51). In conclusion, wearing a water-soaked t-shirt without, but not with, electric fan use is an effective heat management strategy to mitigate thermal strain and lower sweat losses in older individuals exposed to hot and moderately humid conditions.NEW & NOTEWORTHY In older individuals exposed to hot and moderately humid environments, electric fan use coupled with a water-soaked t-shirt exacerbates sweat losses without mitigating heat strain compared with a dry t-shirt. However, wearing a water-soaked t-shirt without fan use reduces sweat losses and attenuates heat strain compared with a dry t-shirt and a fan/water-soaked t-shirt combination. These findings suggest wearing a water-soaked t-shirt is an effective heat-management strategy for older individuals during heat waves when air conditioning is inaccessible.
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Affiliation(s)
- Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
| | - Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas.,Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas.,Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
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Abstract
The US Army's Standards of Medical Fitness, AR 40-501, state that "Prior burn injury (to include donor sites) involving a total body surface area of 40% or more does not meet the standard." Inclusion of donor sites (sites harvested for skin grafts) in this standard implies that thermoregulatory function is impaired within donor sites during exercise-heat stress; however, supporting evidence is currently lacking. PURPOSE To test the hypothesis that well-healed donor and noninjured sites demonstrate similar elevations in skin blood flow and sweating during exercise-induced hyperthermia. METHODS Twenty burn survivors (>1 yr postinjury; four females) cycled for 60 min in a 39.7°C ± 0.3°C and 21.1% ± 3.3% relative humidity environment at approximately 50% of maximal aerobic capacity. Core and mean skin temperatures were recorded throughout exercise. Skin blood flow (laser-Doppler imaging) was measured at baseline and after exercise within donor (LDFDON) and adjacent noninjured control (LDFCON) sites. At 45 min of exercise, local sweat rates (Technical Absorbents) were measured within the same donor (LSRDON) and noninjured (LSRCON) areas. RESULTS After 60 min of exercise, core and skin temperatures reached 38.2°C ± 0.4°C and 35.5°C ± 1.2°C, respectively. The increase in skin blood flow from baseline to end-exercise (LDFDON, 91.6 ± 44.5 AU; LDFCON, 106.0 ± 61.6 AU; P = 0.17) and local sweat rates (LSRDON, 0.46 ± 0.26 mg·cm·min; LSRCON, 0.53 ± 0.25 mg·cm·min; P = 0.14) were not different between donor and noninjured control sites. CONCLUSIONS Well-healed donor sites retain the ability to increase skin blood flow and sweating during exercise heat stress, providing evidence against the inclusion of donor sites when determining whether a burn injury meets the Army's Standards of Medical Fitness.
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Affiliation(s)
- Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
| | - M U Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX.,Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, TX
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Romero SA, Moralez G, Jaffery MF, Huang M, Cramer MN, Romain N, Kouda K, Haller RG, Crandall CG. Progressive exercise training improves maximal aerobic capacity in individuals with well-healed burn injuries. Am J Physiol Regul Integr Comp Physiol 2019; 317:R563-R570. [PMID: 31433672 DOI: 10.1152/ajpregu.00201.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Long-term rehabilitative strategies are important for individuals with well-healed burn injuries. Such information is particularly critical because patients are routinely surviving severe burn injuries given medical advances in the acute care setting. The purpose of this study was to test the hypothesis that a 6-mo community-based exercise training program will increase maximal aerobic capacity (V̇o2max) in subjects with prior burn injuries, with the extent of that increase influenced by the severity of the burn injury (i.e., percent body surface area burned). Maximal aerobic capacity (indirect calorimetry) and skeletal muscle oxidative enzyme activity (biopsy of the vastus lateralis muscle) were measured pre- and postexercise training in noninjured control subjects (n = 11) and in individuals with well-healed burn injuries (n = 13, moderate body surface area burned; n = 20, high body surface area burned). Exercise training increased V̇o2max in all groups (control: 15 ± 5%; moderate body surface area: 11 ± 3%; high body surface area: 11 ± 2%; P < 0.05), though the magnitude of this improvement did not differ between groups (P = 0.7). Exercise training also increased the activity of the skeletal muscle oxidative enzymes citrate synthase (P < 0.05) and cytochrome c oxidase (P < 0.05), an effect that did not differ between groups (P = 0.2). These data suggest that 6 mo of progressive exercise training improves V̇o2max in individuals with burn injuries and that the magnitude of body surface area burned does not lessen this adaptive response.
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Affiliation(s)
- Steven A Romero
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,University of North Texas Health Science Center, Fort Worth, Texas
| | - Gilbert Moralez
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Manall F Jaffery
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Mu Huang
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Matthew N Cramer
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Nadine Romain
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Ken Kouda
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas.,Wakayama Medical University, Wakayama, Japan
| | - Ronald G Haller
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
| | - Craig G Crandall
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, Texas
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Cramer MN, Huang M, Hieda M, Moralez G, Crandall CG. Effect of Dietary Nitrate Supplementation with Beet Root Juice on Thermoregulatory and Cardiovascular Responses to Extreme Heat in Aged Humans. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000562211.68536.fe] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hearon CM, Hansen AB, Moralez G, Romero SA, Levine BD, Lawley JS. Global REACH Expedition: Chronic Hypoxia Attenuates α
1
‐Adrenergic‐Mediated Vasoconstriction in Humans: Mechanisms of “Chronic‐Hypoxic Sympatholysis”. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.838.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Alex B Hansen
- Department of Sport ScienceUniversity of InnsbruckInnsbruckAustria
| | | | - Steven A Romero
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTX
| | | | - Justin S Lawley
- Department of Sport ScienceUniversity of InnsbruckInnsbruckAustria
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Samuel TJ, Nelson MD, Nasirian A, Jaffery M, Moralez G, Romero SA, Cramer MN, Huang M, Kouda K, Babb TG, Sarma S, Crandall C. Impaired pulmonary function and right ventricular morphology in well‐healed burn survivors is related to aerobic capacity and not severity of burn injury. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.535.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- T. Jake Samuel
- KinesiologyThe University of Texas at ArlingtonArlingtonTX
| | | | - Aida Nasirian
- The University of Texas at Arlington Research InstituteFort WorthTX
| | - Manall Jaffery
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Gilbert Moralez
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Steven A. Romero
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTX
| | - Matthew N. Cramer
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Mu Huang
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas SouthwesternDallasTX
| | - Ken Kouda
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Tony G. Babb
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Satyam Sarma
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
| | - Craig Crandall
- Institute for Exercise & Environmental MedicineTexas Health Presbyterian HospitalDallasTX
- Department of Internal MedicineUniversity of Texas Southwestern Medical CenterDallasTX
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Huang M, Moralez G, Cramer MN, Hendrix JM, Hinojosa‐Laborde C, Ryan KL, Crandall CG. Analgesics in the Pre‐Hospital Setting: Simulated Hemorrhagic Tolerance in Humans is not Impaired by Ketamine Administration. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.541.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mu Huang
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTX
| | - Gilbert Moralez
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTX
| | - Matthew N. Cramer
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTX
| | - Joseph M. Hendrix
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTX
| | | | - Kathy L. Ryan
- US Army Institute of Surgical ResearchJBSA Fort Sam HoustonTX
| | - Craig G. Crandall
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTX
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Hearon CM, Hansen AB, Moralez G, Romero SA, Levine BD, Lawley JS. Global REACH Expedition: Chronic Hypoxia Attenuates the Contribution α‐Adrenergic Receptors to Sympathetic Transduction in Exercising Humans. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.562.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Alex B Hansen
- Department of Sport ScienceUniversity of InnsbruckInnsbruckAustria
| | | | - Steven A Romero
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTX
| | | | - Justin S Lawley
- Department of Sport ScienceUniversity of InnsbruckInnsbruckAustria
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Moralez G, Huang M, Cramer MN, Hendrix JM, Hinojosa‐Laborde C, Ryan KL, Fu Q, Crandall CG. Ketamine Blunts Sympathetic Nerve Activity Responses to a Cold Pressor test. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.848.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gilbert Moralez
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
| | - Mu Huang
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
| | - Matthew N Cramer
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
| | - Joseph M Hendrix
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
| | | | - Kathy L Ryan
- US Army Institute of Surgical ResearchJBSAFort Sam HoustonTX
| | - Qi Fu
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
| | - Craig G Crandall
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
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Romero SA, Moralez G, Jaffery MF, Huang M, Crandall CG. Vasodilator function is impaired in burn injury survivors. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1054-R1060. [PMID: 30256680 DOI: 10.1152/ajpregu.00188.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of severe burn injury on vascular health is unknown. We tested the hypothesis that, compared with nonburn control subjects, vasodilator function would be reduced and that pulse-wave velocity (a measure of arterial stiffness) would be increased in individuals with prior burn injuries, the extent of which would be associated with the magnitude of body surface area having sustained a severe burn. Pulse-wave velocity and macrovascular (flow-mediated dilation) and microvascular (reactive hyperemia) dilator functions were assessed in 14 nonburned control subjects and 32 age-matched subjects with well-healed burn injuries. Fifteen subjects with burn injuries covering 17-40% of body surface area were assigned to a moderate burn injury group, and 17 subjects with burn injuries covering >40% of body surface area were assigned to a high burn injury group. Pulse-wave velocity [ P = 0.3 (central) and P = 0.3 (peripheral)] did not differ between the three groups. Macrovascular dilator function was reduced in the moderate ( P = 0.07) and high ( P < 0.05) burn injury groups compared with the control group. Likewise, peak vascular conductance during postocclusive reactive hyperemia differed from the moderate burn injury group ( P = 0.08 vs. control) and the high burn injury group ( P < 0.05 vs. control). These data suggest that vasodilator function is impaired in well-healed burn injury survivors, with the extent of impairment not dependent on the magnitude of body surface area having sustained a severe burn injury.
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Affiliation(s)
- Steven A Romero
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital , Dallas, Texas.,University of North Texas Health Science Center, Ft. Worth, Texas
| | - Gilbert Moralez
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital , Dallas, Texas
| | - Manall F Jaffery
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital , Dallas, Texas
| | - Mu Huang
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital , Dallas, Texas
| | - Craig G Crandall
- University of Texas Southwestern Medical Center and Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital , Dallas, Texas
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Huang M, Brothers RM, Ganio MS, Lucas RAI, Cramer MN, Moralez G, Convertino VA, Crandall CG. Tolerance to a haemorrhagic challenge during heat stress is improved with inspiratory resistance breathing. Exp Physiol 2018; 103:1243-1250. [PMID: 29947436 PMCID: PMC6119106 DOI: 10.1113/ep087102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/22/2018] [Indexed: 02/06/2023]
Abstract
NEW FINDINGS What is the central question of this study? Does inspiratory resistance breathing improve tolerance to simulated haemorrhage in individuals with elevated internal temperatures? What is the main finding and its importance? The main finding of this study is that inspiratory resistance breathing modestly improves tolerance to a simulated progressive haemorrhagic challenge during heat stress. These findings demonstrate a scenario in which exploitation of the respiratory pump can ameliorate serious conditions related to systemic hypotension. ABSTRACT Heat exposure impairs human blood pressure control and markedly reduces tolerance to a simulated haemorrhagic challenge. Inspiratory resistance breathing enhances blood pressure control and improves tolerance during simulated haemorrhage in normothermic individuals. However, it is unknown whether similar improvements occur with this manoeuvre in heat stress conditions. In this study, we tested the hypothesis that inspiratory resistance breathing improves tolerance to simulated haemorrhage in individuals with elevated internal temperatures. On two separate days, eight subjects performed a simulated haemorrhage challenge [lower-body negative pressure (LBNP)] to presyncope after an increase in internal temperature of 1.3 ± 0.1°C. During one trial, subjects breathed through an inspiratory impedance device set at 0 cmH2 O of resistance (Sham), whereas on a subsequent day the device was set at -7 cmH2 O of resistance (ITD). Tolerance was quantified as the cumulative stress index. Subjects were more tolerant to the LBNP challenge during the ITD protocol, as indicated by a > 30% larger cumulative stress index (Sham, 520 ± 306 mmHg min; ITD, 682 ± 324 mmHg min; P < 0.01). These data indicate that inspiratory resistance breathing modestly improves tolerance to a simulated progressive haemorrhagic challenge during heat stress.
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Affiliation(s)
- Mu Huang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - R Matthew Brothers
- Department of Kinesiology, University of Texas, Arlington, Arlington, TX, USA
| | - Matthew S Ganio
- Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Rebekah A I Lucas
- School of Sport, Exercise & Rehabilitation Sciences, The University of Birmingham, Edgbaston, Birmingham, UK
| | - Matthew N Cramer
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Moralez G, Jouett NP, Tian J, Zimmerman MC, Bhella P, Raven PB. Effect of centrally acting angiotensin converting enzyme inhibitor on the exercise-induced increases in muscle sympathetic nerve activity. J Physiol 2018; 596:2315-2332. [PMID: 29635787 PMCID: PMC6002210 DOI: 10.1113/jp274697] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 03/21/2018] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS The arterial baroreflex's operating point pressure is reset upwards and rightwards from rest in direct relation to the increases in dynamic exercise intensity. The intraneural pathways and signalling mechanisms that lead to upwards and rightwards resetting of the operating point pressure, and hence the increases in central sympathetic outflow during exercise, remain to be identified. We tested the hypothesis that the central production of angiotensin II during dynamic exercise mediates the increases in sympathetic outflow and, therefore, the arterial baroreflex operating point pressure resetting during acute and prolonged dynamic exercise. The results identify that perindopril, a centrally acting angiotensin converting enzyme inhibitor, markedly attenuates the central sympathetic outflow during acute and prolonged dynamic exercise. ABSTRACT We tested the hypothesis that the signalling mechanisms associated with the dynamic exercise intensity related increases in muscle sympathetic nerve activity (MSNA) and arterial baroreflex resetting during exercise are located within the central nervous system. Participants performed three randomly ordered trials of 70° upright back-supported dynamic leg cycling after ingestion of placebo and two different lipid soluble angiotensin converting enzyme inhibitors (ACEi): perindopril (high lipid solubility), captopril (low lipid solubility). Repeated measurements of whole venous blood (n = 8), MSNA (n = 7) and arterial blood pressures (n = 14) were obtained at rest and during an acute (SS1) and prolonged (SS2) bout of steady state dynamic exercise. Arterial baroreflex function curves were modelled at rest and during exercise. Peripheral venous superoxide concentrations measured by electron spin resonance spectroscopy were elevated during exercise and were not altered by ACEi at rest (P ≥ 0.4) or during exercise (P ≥ 0.3). Baseline MSNA and mean arterial pressure were unchanged at rest (P ≥ 0.1; P ≥ 0.8, respectively). However, during both SS1 and SS2, the centrally acting ACEi perindopril attenuated MSNA compared to captopril and the placebo (P < 0.05). Arterial pressures at the operating point and threshold pressures were decreased with perindopril from baseline to SS1 with no further changes in the operating point pressure during SS2 under all three conditions. These data suggest that centrally acting ACEi is significantly more effective at attenuating the increase in the acute and prolonged exercise-induced increases in MSNA.
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Affiliation(s)
- Gilbert Moralez
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and The University of Texas Southwestern Medical CenterDallasTXUSA
| | - Noah P. Jouett
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
| | - Jun Tian
- Department of Cellular and Integrative PhysiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Matthew C. Zimmerman
- Department of Cellular and Integrative PhysiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Paul Bhella
- Department of Cardiac Imaging at the John Peter Smith Health NetworkFort WorthTXUSA
- Department of Internal MedicineTCU and UNTHSC School of MedicineFort WorthTXUSA
| | - Peter B. Raven
- Institute for Cardiovascular and Metabolic DiseaseUniversity of North Texas Health Science CenterFort WorthTXUSA
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Cramer MN, Moralez G, Huang M, Crandall CG. No Evidence Of Thermoregulatory Impairment In Donor Skin During Exercise-induced Hyperthermia. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000537138.61350.e4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Huang M, Jaffery MF, Moralez G, Cramer MN, Romero SA, Crandall CG. Mismatch Between Perception of Disability and Functional Outcomes in Individuals with Large Burn Injuries. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535380.55153.d8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Moralez G, Romero SA, Cramer MN, Adams AN, Jaffery MF, Huang M, Crandall CG. Cardiovascular Responses To Steady State Exercise In Well-healed Burned Survivors After Six Months Of Exercise Training. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000536902.01461.09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cramer MN, Moralez G, Huang M, Crandall CG. Critical Environmental Limits for Prolonged Work in the Heat Using a Simulated Burn Injury Model. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.590.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Matthew N. Cramer
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
| | - Gilbert Moralez
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
| | - Mu Huang
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
- School of Health ProfessionsUniversity of Texas Southwestern Medical CenterDallasTX
| | - Craig G. Crandall
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical CenterDallasTX
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Moralez G, Hieda M, Sarma S, Romero SA, Cramer MN, Huang M, Crandall CG. Left ventricular systolic function is improved in well‐healed burn survivors after six months of exercise training. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.855.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gilbert Moralez
- Internal Medicine, CardiologyUT Southwestern Medical Center and Institute for Exercise and Environmental MedicineDallasTX
| | - Michinari Hieda
- Internal Medicine, CardiologyUT Southwestern Medical Center and Institute for Exercise and Environmental MedicineDallasTX
| | - Satyam Sarma
- Internal Medicine, CardiologyUT Southwestern Medical Center and Institute for Exercise and Environmental MedicineDallasTX
| | - Steven A. Romero
- Department of Physiology and AnatomyUniversity of North Texas Health Science CenterFort WorthTX
| | - Matthew N. Cramer
- Internal Medicine, CardiologyUT Southwestern Medical Center and Institute for Exercise and Environmental MedicineDallasTX
| | - Mu Huang
- Internal Medicine, CardiologyUT Southwestern Medical Center and Institute for Exercise and Environmental MedicineDallasTX
| | - Craig G. Crandall
- Internal Medicine, CardiologyUT Southwestern Medical Center and Institute for Exercise and Environmental MedicineDallasTX
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