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Ratchford SM, Broxterman RM, La Salle DT, Kwon OS, Hopkins PN, Richardson RS, Trinity JD. Obesity does not alter vascular function and handgrip exercise hemodynamics in middle-aged patients with hypertension. Am J Physiol Regul Integr Comp Physiol 2024; 326:R1-R9. [PMID: 37842741 DOI: 10.1152/ajpregu.00105.2023] [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: 05/10/2023] [Revised: 09/19/2023] [Accepted: 10/09/2023] [Indexed: 10/17/2023]
Abstract
Lifestyle modification including exercise training is often the first line of defense in the treatment of obesity and hypertension (HTN), however, little is known regarding how these potentially compounding disease states impact vasodilatory and hemodynamic responses at baseline and exercise. Therefore, this study sought to compare the impact of obesity on vascular function and hemodynamics at baseline and during handgrip (HG) exercise among individuals with HTN. Non-obese (13M/7F, 56 ± 16 yr, 25 ± 4 kg/m2) and obese (17M/4F, 50 ± 7 yr, 35 ± 4 kg/m2) middle-aged individuals with HTN forwent antihypertensive medication use for ≥2 wk before assessment of vascular function by brachial artery flow-mediated dilation (FMD) and exercise hemodynamics during progressive HG exercise at 15-30-45% maximal voluntary contraction (MVC). FMD was not different between Non-Obese (4.1 ± 1.7%) and Obese (5.2 ± 1.9%, P = 0.11). Systolic blood pressure (SBP) was elevated by ∼15% during the supine baseline and during HG exercise in the obese group. The blood flow response to HG exercise at 30% and 45% MVC was ∼20% greater (P < 0.05) in the obese group but not different after normalizing for the higher, albeit, nonsignificant differences in workloads (MVC: obese: 24 ± 5 kg, non-obese: 21 ± 5 kg, P = 0.11). Vascular conductance and the brachial artery shear-induced vasodilatory response during HG were not different between groups (P > 0.05). Taken together, despite elevated SBP during HG exercise, obesity does not lead to additional impairments in vascular function and peripheral exercising hemodynamics in patients with HTN. Obesity may not be a contraindication when prescribing exercise for the treatment of HTN among middle-aged adults, however, the elevated SBP should be appropriately monitored.NEW & NOTEWORTHY This study examined vascular function and handgrip exercise hemodynamics in obese and nonobese individuals with hypertension. Obesity, when combined with hypertension, was neither associated with additional vascular function impairments at baseline nor peripheral hemodynamics and vasodilation during exercise compared with nonobese hypertension. Interestingly, systolic blood pressure and pulse pressure were greater in the obese group during supine baseline and exercise. These findings should not be ignored and may be particularly important for rehabilitation strategies.
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Affiliation(s)
- Stephen M Ratchford
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
| | - Ryan M Broxterman
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
| | - D Taylor La Salle
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Oh Sung Kwon
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut, United States
| | - Paul N Hopkins
- Department of Internal Medicine, Division of Cardiovascular Genetics, University of Utah, Salt Lake City, Utah, United States
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, George E. Whalen Veteran Affairs Medical Center, Salt Lake City, Utah, United States
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, United States
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Ichinose M, Nakabayashi M, Ono Y. Rapid vasodilation within contracted skeletal muscle in humans: new insight from concurrent use of diffuse correlation spectroscopy and Doppler ultrasound. Am J Physiol Heart Circ Physiol 2020; 320:H654-H667. [PMID: 33337963 DOI: 10.1152/ajpheart.00761.2020] [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] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies showed that conduit artery blood flow rapidly increases after even a brief contraction of muscles within the dependent limb. Whether this rapid hyperemia occurs within contracted skeletal muscle in humans has yet to be confirmed, however. We therefore used diffuse correlation spectroscopy (DCS) to characterize the rapid hyperemia and vasodilatory responses within the muscle microvasculature induced by single muscle contractions in humans. Twenty-five healthy male volunteers performed single 1-s isometric handgrips at 20%, 40%, 60%, and 80% of maximum voluntary contraction. DCS probes were placed on the flexor digitorum superficialis muscle, and a skeletal muscle blood flow index (SMBFI) was derived continuously. At the same time, brachial artery blood flow (BABF) responses were measured using Doppler ultrasound. Single muscle contractions evoked rapid, monophasic increases in both SMBFI and BABF that occurred within 3 s after release of contraction. The initial and peak responses increased with increases in contraction intensity and were greater for BABF than for SMBFI at all intensities. BABF reached its peak within 5 to 8 s after the end of contraction. The SMBFI continued to increase after the BABF passed its peak and was decreasing toward the resting level and peaked about 10 to 15 s after completion of the contraction. We conclude that single muscle contractions induce rapid, intensity-dependent hyperemia within the contracted skeletal muscle microvasculature. Moreover, the characteristics of the rapid hyperemia and vasodilatory responses of skeletal muscle microvessels differ from those simultaneously evaluated in the upstream conduit artery.NEW & NOTEWORTHY Through the concurrent use of diffuse correlation spectroscopy and Doppler ultrasound, we provide the first evidence in humans that a single brief muscle contraction evokes rapid, intensity-dependent hyperemia within the contracted skeletal muscle microvasculature and the upstream conduit artery. We also show that the magnitude and time course of the contraction-induced rapid hyperemia and vasodilatory responses within skeletal muscle microvessels significantly differ from those in the conduit artery.
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Affiliation(s)
- Masashi Ichinose
- Human Integrative Physiology Laboratory, School of Business Administration, Meiji University, Tokyo, Japan
| | - Mikie Nakabayashi
- Graduate School of Science and Technology, Meiji University, Kanagawa, Japan
| | - Yumie Ono
- Department of Electronics and Bioinformatics, School of Science and Technology, Meiji University, Kanagawa, Japan
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El Agaty SM, Kirmani A, Labban E. Heart rate variability analysis during immediate recovery from exercise in overweight/obese healthy young adult females. Ann Noninvasive Electrocardiol 2016; 22. [PMID: 28012220 DOI: 10.1111/anec.12427] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [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: 12/31/2022] Open
Abstract
BACKGROUND Data on heart rate variability (HRV) changes during immediate recovery period after exercise in overweight/obese healthy young adult females are still inconclusive. The aim of this study was to evaluate the heart rate variability (HRV), heart rate recovery (HRR), and arterial blood pressure immediately after cessation of exercise in overweight/obese healthy young adult females. METHODS This study was carried out in the laboratory of the Physiology Department, Faculty of Medicine, King Abdulaziz University. Fifty-five female students were classified into normal weight group and overweight/obese group. HRV, HRR, and systolic and diastolic blood pressures (SBP, DBP) were estimated at resting condition and immediately after cessation of exercise. RESULTS During recovery, heart rate was significantly increased in overweight/obese group along with significant decrease in rMSSD (square root of the mean of the sum of the squares of differences between adjacent NN intervals) and HF (high-frequency power) compared with normal group. The recovery of heart rate, normalized HF, and normalized sympathovagal balance to their baseline values were significantly lowered in overweight/obese group. Both SBP and DBP were significantly lowered from their baseline values during recovery in normal group but unchanged in overweight/obese group. CONCLUSIONS This study provides evidence that overweight/obesity are associated with decreased HRR and delayed vagal reactivation, in addition to impaired postexercise hypotension early in the recovery period after exercise in healthy young adult females.
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Affiliation(s)
- Sahar M El Agaty
- Physiology Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Azra Kirmani
- Physiology Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ezaz Labban
- Physiology Department, Faculty of Medicine, Umm Al-Qura University, Makka, Saudi Arabia
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Hughes WE, Ueda K, Casey DP. Chronic endurance exercise training offsets the age-related attenuation in contraction-induced rapid vasodilation. J Appl Physiol (1985) 2016; 120:1335-42. [PMID: 27032899 DOI: 10.1152/japplphysiol.00057.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [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: 01/19/2016] [Accepted: 03/25/2016] [Indexed: 01/25/2023] Open
Abstract
Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). We sought to examine whether chronic exercise training would improve ROV in older adults. Additionally, we examined whether a relationship between cardiorespiratory fitness and ROV exists in young and older adults. Chronically exercise-trained older adults (n = 16; 66 ± 2 yr, mean ± SE) performed single muscle contractions in the forearm and leg at various intensities. Brachial and femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC) was calculated as the quotient of blood flow (ml/min) and mean arterial pressure (mmHg). These data were compared with our previously published work from an identical protocol in 16 older untrained (66 ± 1 yr, mean ± SE) and 14 young (23 ± 1 yr) adults. Peak (ΔVCpeak) and total vasodilator (VCtotal) responses were greater in trained compared with untrained older adults across leg exercise intensities (P < 0.05). There were no differences in responses between trained older and young adults in the arm or leg at any exercise intensity (P > 0.05). Comparison of ΔVCpeak in a subset of subjects at an absolute workload in the leg revealed that trained older adults exhibited augmented responses relative to untrained older adults. Exercise capacity (V̇o2 peak) was associated with ΔVCpeak and VCtotal across arm (r = 0.59-0.64) and leg exercise intensities (r = 0.55-0.68, P < 0.05) in older adults. Our data demonstrate that 1) chronic exercise training improves ROV in the arm and leg of trained older adults, such that age-related differences in ROV are abolished, and 2) VO2peak is associated with ΔVCpeak responses in both limbs of older adults.
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Affiliation(s)
| | - Kenichi Ueda
- Department of Anesthesia, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science; Abboud Cardiovascular Research Center; Fraternal Order of Eagles Diabetes Research; and
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Credeur DP, Holwerda SW, Restaino RM, King PM, Crutcher KL, Laughlin MH, Padilla J, Fadel PJ. Characterizing rapid-onset vasodilation to single muscle contractions in the human leg. J Appl Physiol (1985) 2014; 118:455-64. [PMID: 25539935 DOI: 10.1152/japplphysiol.00785.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [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] Open
Abstract
Rapid-onset vasodilation (ROV) following single muscle contractions has been examined in the forearm of humans, but has not yet been characterized in the leg. Given known vascular differences between the arm and leg, we sought to characterize ROV following single muscle contractions in the leg. Sixteen healthy men performed random ordered single contractions at 5, 10, 20, 40, and 60% of their maximum voluntary contraction (MVC) using isometric knee extension made with the leg above and below heart level, and these were compared with single isometric contractions of the forearm (handgrip). Single thigh cuff compressions (300 mmHg) were utilized to estimate the mechanical contribution to leg ROV. Continuous blood flow was determined by duplex-Doppler ultrasound and blood pressure via finger photoplethysmography (Finometer). Single isometric knee extensor contractions produced intensity-dependent increases in peak leg vascular conductance that were significantly greater than the forearm in both the above- and below-heart level positions (e.g., above heart level: leg 20% MVC, +138 ± 28% vs. arm 20% MVC, +89 ± 17%; P < 0.05). Thigh cuff compressions also produced a significant hyperemic response, but these were brief and smaller in magnitude compared with single isometric contractions in the leg. Collectively, these data demonstrate the presence of a rapid and robust vasodilation to single muscle contractions in the leg that is largely independent of mechanical factors, thus establishing the leg as a viable model to study ROV in humans.
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Affiliation(s)
- Daniel P Credeur
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Seth W Holwerda
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Robert M Restaino
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Phillip M King
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Kiera L Crutcher
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - M Harold Laughlin
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Department of Biomedical Sciences, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Jaume Padilla
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; and Department of Child Health, University of Missouri, Columbia, Missouri
| | - Paul J Fadel
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri;
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Ross AJ, Muller MD. Implications of the rapid onset exercise pressor reflex in hypertension. J Hum Hypertens 2014; 29:400-1. [PMID: 25471614 DOI: 10.1038/jhh.2014.107] [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: 11/09/2022]
Affiliation(s)
- A J Ross
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, PA, USA
| | - M D Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Hershey, PA, USA
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Limberg JK, Kellawan JM, Harrell JW, Johansson RE, Eldridge MW, Proctor LT, Sebranek JJ, Schrage WG. Exercise-mediated vasodilation in human obesity and metabolic syndrome: effect of acute ascorbic acid infusion. Am J Physiol Heart Circ Physiol 2014; 307:H840-7. [PMID: 25038148 DOI: 10.1152/ajpheart.00312.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [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
We tested the hypothesis that infusion of ascorbic acid (AA), a potent antioxidant, would alter vasodilator responses to exercise in human obesity and metabolic syndrome (MetSyn). Forearm blood flow (FBF, Doppler ultrasound) was measured in lean, obese, and MetSyn adults (n = 39, 32 ± 2 yr). A brachial artery catheter was inserted for blood pressure monitoring and local infusion of AA. FBF was measured during dynamic handgrip exercise (15% maximal effort) with and without AA infusion. To account for group differences in blood pressure and forearm size, and to assess vasodilation, forearm vascular conductance (FVC = FBF/mean arterial blood pressure/lean forearm mass) was calculated. We examined the time to achieve steady-state FVC (mean response time, MRT) and the rise in FVC from rest to steady-state exercise (Δ, exercise - rest) before and during acute AA infusion. The MRT (P = 0.26) and steady-state vasodilator responses to exercise (ΔFVC, P = 0.31) were not different between groups. Intra-arterial infusion of AA resulted in a significant increase in plasma total antioxidant capacity (174 ± 37%). AA infusion did not alter MRT or steady-state FVC in any group (P = 0.90 and P = 0.85, respectively). Interestingly, higher levels of C-reactive protein predicted longer MRT (r = 0.52, P < 0.01) and a greater reduction in MRT with AA infusion (r = -0.43, P = 0.02). We concluded that AA infusion during moderate-intensity, rhythmic forearm exercise does not alter the time course or magnitude of exercise-mediated vasodilation in groups of young lean, obese, or MetSyn adults. However, systemic inflammation may limit the MRT to exercise, which can be improved with AA.
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Affiliation(s)
| | - J Mikhail Kellawan
- Department of Kinesiology, School of Education, University of Wisconsin, and
| | - John W Harrell
- Department of Kinesiology, School of Education, University of Wisconsin, and
| | - Rebecca E Johansson
- Department of Kinesiology, School of Education, University of Wisconsin, and
| | | | - Lester T Proctor
- Anesthesiology, School of Medicine and Public Health, University of Wisconsin Hospital and Clinics, Madison, Wisconsin
| | - Joshua J Sebranek
- Anesthesiology, School of Medicine and Public Health, University of Wisconsin Hospital and Clinics, Madison, Wisconsin
| | - William G Schrage
- Department of Kinesiology, School of Education, University of Wisconsin, and
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8
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Novielli NM, Jackson DN. Contraction-evoked vasodilation and functional hyperaemia are compromised in branching skeletal muscle arterioles of young pre-diabetic mice. Acta Physiol (Oxf) 2014; 211:371-84. [PMID: 24703586 DOI: 10.1111/apha.12297] [Citation(s) in RCA: 10] [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] [Received: 10/09/2013] [Revised: 12/14/2013] [Accepted: 03/28/2014] [Indexed: 12/25/2022]
Abstract
AIM To investigate the effects of pre-diabetes on microvascular network function in contracting skeletal muscle. We hypothesized that pre-diabetes compromises contraction-evoked vasodilation of branching second-order (2A), third-order (3A) and fourth-order (4A) arterioles, where distal arterioles would be affected the greatest. METHODS Intravital video microscopy was used to measure arteriolar diameter (in 2A, 3A and 4A) and blood flow (in 2A and 3A) changes to electrical field stimulation of the gluteus maximus muscle in pre-diabetic (The Pound Mouse, PD) and control (c57bl6, CTRL) mice. RESULTS Baseline diameter and blood flow were similar between groups (2A: ~20 μm, 3A: ~14 μm and 4A: ~8 μm; 2A: ~1 nL s(-1) and 3A: ~0.5 nL s(-1) ). Single tetanic contraction (100 Hz; 200, 400, 800 ms duration) evoked rapid-onset vasodilation (ROV) and blood flow responses that were blunted by ~50% and up to 81%, respectively, in PD vs. CTRL (P < 0.05). The magnitude of ROV was up to 2-fold greater at distal arterioles (3A and 4A) vs. proximal arterioles (2A) in CTRL; however, in PD, ROV of only 4A was greater than 2A (P < 0.05). Rhythmic contraction (2 and 8 Hz, 30 s) evoked vasodilatory and blood flow responses that were also attenuated by ~50% and up to 71%, respectively, in PD vs. CTRL (P < 0.05). The magnitude of vasodilatory responses to rhythmic contraction was also up to 2.5-fold greater at 4A vs. 2A in CTRL; however spatial differences in vasodilation across arteriolar branch orders was disrupted in PD. CONCLUSIONS Arteriolar dysregulation in pre-diabetes causes deficits in contraction-evoked dilation and blood flow, where greatest deficits occur at distal arterioles.
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Affiliation(s)
- N. M. Novielli
- Department of Medical Biophysics; Western University; London ON Canada
| | - D. N. Jackson
- Department of Medical Biophysics; Western University; London ON Canada
- Biomedical Engineering Graduate Program; Western University; London ON Canada
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9
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Affiliation(s)
- A. Zietzer
- Charité - Universitaetsmedizin Berlin; Center for Cardiovascular Research & Experimental and Clinical Research Center; Richard-Thoma-Laboratories for Arteriogenesis; Berlin Germany
| | - P. Hillmeister
- Charité - Universitaetsmedizin Berlin; Center for Cardiovascular Research & Experimental and Clinical Research Center; Richard-Thoma-Laboratories for Arteriogenesis; Berlin Germany
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10
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Affiliation(s)
- S. Reuter
- Klinik für Innere Medizin III; AG Experimentelle Nephrologie; Universitätsklinikum Jena; Jena Germany
| | - A. Patzak
- Institut für Vegetative Physiologie; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - R. Mrowka
- Klinik für Innere Medizin III; AG Experimentelle Nephrologie; Universitätsklinikum Jena; Jena Germany
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11
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Affiliation(s)
- K. Schmerbach
- Charité-Universitätsmedizin Berlin; Institut für Vegetative Physiologie; Berlin Germany
| | - A. Patzak
- Charité-Universitätsmedizin Berlin; Institut für Vegetative Physiologie; Berlin Germany
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12
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Casey DP, Walker BG, Ranadive SM, Taylor JL, Joyner MJ. Contribution of nitric oxide in the contraction-induced rapid vasodilation in young and older adults. J Appl Physiol (1985) 2013; 115:446-55. [PMID: 23788575 DOI: 10.1152/japplphysiol.00446.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [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] Open
Abstract
We tested the hypothesis that reduced nitric oxide (NO) bioavailability contributes to the attenuated peak and total vasodilation following single-muscle contractions in older adults. Young (n = 10; 24 ± 2 yr) and older (n = 10; 67 ± 2 yr) adults performed single forearm contractions at 10, 20, and 40% of maximum during saline infusion (control) and NO synthase (NOS) inhibition via N(G)-monomethyl-l-arginine. Brachial artery diameters and velocities were measured using Doppler ultrasound and forearm vascular conductance (FVC; in ml·min(-1)·100 mmHg(-1)) was calculated from blood flow (ml/min) and blood pressure (mmHg). Peak and total vasodilator responses [change (Δ) in FVC from baseline] were attenuated in older adults at all intensities (P < 0.05). NOS inhibition reduced the peak ΔFVC at 10% (88 ± 12 vs. 52 ± 9 ml·min(-1)·100 mmHg(-1)), 20% (125 ± 13 vs. 83 ± 13 ml·min(-1)·100 mmHg(-1)), and 40% (207 ± 26 vs. 133 ± 20 ml·min(-1)·100 mmHg(-1)) in young subjects, (P < 0.05 for all) and in older adults at 10% (59 ± 5 vs. 47 ± 7 ml·min(-1)·100 mmHg(-1), P < 0.05) and 20% (88 ± 9 vs. 68 ± 9 ml·min(-1)·100 mmHg(-1), P < 0.05), but not 40% (128 ± 12 vs. 105 ± 11 ml·min(-1)·100 mmHg(-1), P = 0.11). The relative (%) reduction in peak ΔFVC due to NOS inhibition was greater in young vs. older adults at 20% (-36 ± 5 vs. -23 ± 5%, P < 0.05) and 40% (-35 ± 6 vs. -16 ± 7%, P < 0.05). The reduction in the total vasodilator response (area under the curve) with NOS inhibition was also greater in young vs. older adults at all intensities. Our data suggest that contraction-induced rapid vasodilation is mediated in part by NO, and that the contribution of NO is greater in young adults.
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Affiliation(s)
- Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
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13
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Crecelius AR, Kirby BS, Luckasen GJ, Larson DG, Dinenno FA. Mechanisms of rapid vasodilation after a brief contraction in human skeletal muscle. Am J Physiol Heart Circ Physiol 2013; 305:H29-40. [PMID: 23645465 DOI: 10.1152/ajpheart.00298.2013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [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
A monophasic increase in skeletal muscle blood flow is observed after a brief single forearm contraction in humans, yet the underlying vascular signaling pathways remain largely undetermined. Evidence from experimental animals indicates an obligatory role of vasodilation via K⁺-mediated smooth muscle hyperpolarization, and human data suggest little to no independent role for nitric oxide (NO) or vasodilating prostaglandins (PGs). We tested the hypothesis that K⁺-mediated vascular hyperpolarization underlies the rapid vasodilation in humans and that combined inhibition of NO and PGs would have a minimal effect on this response. We measured forearm blood flow (Doppler ultrasound) and calculated vascular conductance 10 s before and for 30 s after a single 1-s dynamic forearm contraction at 10%, 20%, and 40% maximum voluntary contraction in 16 young adults. To inhibit K⁺-mediated vasodilation, BaCl₂ and ouabain were infused intra-arterially to inhibit inwardly rectifying K⁺ channels and Na⁺-K⁺-ATPase, respectively. Combined enzymatic inhibition of NO and PG synthesis occurred via NG-monomethyl-L-arginine (L-NMMA; NO synthase) and ketorolac (cyclooxygenase), respectively. In protocol 1 (n = 8), BaCl₂ + ouabain reduced peak vasodilation (range: 30-45%, P < 0.05) and total postcontraction vasodilation (area under the curve, ~55-75% from control) at all intensities. Contrary to our hypothesis, L-NMMA + ketorolac had a further impact (peak: ~60% and area under the curve: ~80% from control). In protocol 2 (n = 8), the order of inhibitors was reversed, and the findings were remarkably similar. We conclude that K⁺-mediated hyperpolarization and NO and PGs, in combination, significantly contribute to contraction-induced rapid vasodilation and that inhibition of these signaling pathways nearly abolishes this phenomenon in humans.
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Affiliation(s)
- Anne R Crecelius
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA
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14
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Affiliation(s)
- P. B. Persson and
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin Berlin; Berlin; Germany
| | - A. Bondke Persson
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin Berlin; Berlin; Germany
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15
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Affiliation(s)
- P. B. Persson
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin Berlin; Berlin; Germany
| | - A. Bondke Persson
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin Berlin; Berlin; Germany
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16
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Dipla K, Nassis GP, Vrabas IS. Blood Pressure Control at Rest and during Exercise in Obese Children and Adults. J Obes 2012; 2012:147385. [PMID: 22666555 PMCID: PMC3361254 DOI: 10.1155/2012/147385] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/19/2012] [Accepted: 03/01/2012] [Indexed: 11/17/2022] Open
Abstract
The hemodynamic responses to exercise have been studied to a great extent over the past decades, and an exaggerated blood pressure response during an acute exercise bout has been considered as an indicator of cardiovascular risk. Obesity is a major factor influencing the blood pressure response to exercise since evidence indicates that the arterial pressure response to exercise is exacerbated in obese compared with lean adults. Signs of augmented responses (such as an exaggerated blood pressure response) to physical exertion appear early in life (from the prepubertal years) in obese individuals. Understanding the mechanisms that drive the altered hemodynamic responses during exercise in obese individuals and prevent the progression to hypertension is vitally important. This paper focuses on the evidence linking obesity with alterations of the autonomic nervous system and discusses the potential mechanisms and consequences of the altered sympathetic nervous system behavior in obese individuals at rest and during exercise. Furthermore, this paper presents the alterations in the reflex regulatory mechanisms ("exercise pressor reflex" and baroreflex) in obese children and adults and addresses the effects of training on obesity-related disturbances.
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Affiliation(s)
- Konstantina Dipla
- Exercise Physiology and Biochemistry Laboratory, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Agios Ioannis, 62110 Serres, Greece
- *Konstantina Dipla:
| | - George P. Nassis
- Department of Sport Medicine and Biology of Exercise, Faculty of Physical Education and Sport Science, University of Athens, 17237 Daphne, Greece
| | - Ioannis S. Vrabas
- Exercise Physiology and Biochemistry Laboratory, Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki, Agios Ioannis, 62110 Serres, Greece
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