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Deming N, Steer S, Hernandez J, Dinenno F, Richards J. Carbohydrate ingestion attenuates the reduction in complex cognitive function and cerebral blood flow during prolonged passive heat stress in humans. J Therm Biol 2023; 117:103698. [PMID: 37734348 DOI: 10.1016/j.jtherbio.2023.103698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/07/2023] [Accepted: 08/23/2023] [Indexed: 09/23/2023]
Abstract
PURPOSE To determine whether carbohydrate ingestion would reduce cognitive dysfunction in humans following long duration passive heat stress (PHS) versus consuming electrolytes alone. METHODS Fifteen young (27 ± 4 y) healthy adults were exposed to 120 min of PHS through the use of a liquid perfused suit (50 °C) on two randomized visits. Subjects consumed fluids supplemented with electrolytes (E) or electrolytes + carbohydrates (E + C). Pre- and post-heat stress, body mass (BM) and plasma osmolality (pOsm) were measured. Heart rate (HR), blood pressure (BP), Physiological Strain Index (PSI), core temperature (Tc), plasma glucose, respiration rate (RR), end-tidal CO2 (PetCO2) and internal carotid artery (ICA) blood flow were recorded at baseline and every 15 min of heat stress. Cognitive function was assessed via the Automated Neuropsychological Assessment Metric at baseline and at 30- and 120 min during heat stress. RESULTS There were no significant differences between fluid conditions for BM, pOsm, PSI, Tc, RR or PetCO2. Plasma glucose was ∼75% greater in the E + C condition compared to the E condition after 90 min of PHS (P < 0.05). Cognitive function (120 min) was impaired following PHS only in E condition (P < 0.05) and performance on complex cognitive tasks were better by ∼22-340% in the E + C vs. E (P < 0.05). Compared to the E condition, HR and BP were lower and ICA blood flow, vascular conductance, and glucose delivery was ∼90% greater in the E + C after 90 min of PHS (P < 0.05). CONCLUSIONS These data are the first to demonstrate that carbohydrate ingestion may have a protective effect on cognitive function during long duration PHS. Furthermore, this protection was associated with preserved ICA blood flow and glucose delivery to the brain.
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Affiliation(s)
- Nathan Deming
- Human Performance Laboratory, Directorate of Athletics, USAF Academy, CO, 80840, USA; Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA
| | - Sarah Steer
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA
| | - Jesse Hernandez
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA
| | - Frank Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA
| | - Jennifer Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA.
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Hess HW, Stooks JJ, Baker TB, Chapman CL, Johnson BD, Pryor RR, Basile DP, Monroe JC, Hostler D, Schlader ZJ. Kidney injury risk during prolonged exposure to current and projected wet bulb temperatures occurring during extreme heat events in healthy young men. J Appl Physiol (1985) 2022; 133:27-40. [PMID: 35616302 PMCID: PMC9236880 DOI: 10.1152/japplphysiol.00601.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 11/22/2022] Open
Abstract
Wet bulb temperatures (Twet) during extreme heat events are commonly 31°C. Recent predictions indicate that Twet will approach or exceed 34°C. Epidemiological data indicate that exposure to extreme heat events increases kidney injury risk. We tested the hypothesis that kidney injury risk is elevated to a greater extent during prolonged exposure to Twet = 34°C compared with Twet = 31°C. Fifteen healthy men rested for 8 h in Twet = 31 (0)°C and Twet = 34 (0)°C. Insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinase 2 (TIMP-2), and thioredoxin 1 (TRX-1) were measured from urine samples. The primary outcome was the product of IGFBP7 and TIMP-2 ([IGFBP7·TIMP-2]), which provided an index of kidney injury risk. Plasma interleukin-17a (IL-17a) was also measured. Data are presented at preexposure and after 8 h of exposure and as mean (SD) change from preexposure. The increase in [IGFBP7·TIMP-2] was markedly greater at 8 h in the 34°C [+26.9 (27.1) (ng/mL)2/1,000) compared with the 31°C [+6.2 (6.5) (ng/mL)2/1,000] trial (P < 0.01). Urine TRX-1, a marker of renal oxidative stress, was higher at 8 h in the 34°C [+77.6 (47.5) ng/min] compared with the 31°C [+16.2 (25.1) ng/min] trial (P < 0.01). Plasma IL-17a, an inflammatory marker, was elevated at 8 h in the 34°C [+199.3 (90.0) fg/dL; P < 0.01] compared with the 31°C [+9.0 (95.7) fg/dL] trial. Kidney injury risk is exacerbated during prolonged resting exposures to Twet experienced during future extreme heat events (34°C) compared with that experienced currently (31°C), likely because of oxidative stress and inflammatory processes.NEW AND NOTEWORTHY We have demonstrated that kidney injury risk is increased when men are exposed over an 8-h period to a wet bulb temperature of 31°C and exacerbated at a wet bulb temperature of 34°C. Importantly, these heat stress conditions parallel those that are encountered during current (31°C) and future (34°C) extreme heat events. The kidney injury biomarker analyses indicate both the proximal and distal tubules as the locations of potential renal injury and that the injury is likely due to oxidative stress and inflammation.
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Affiliation(s)
- Hayden W Hess
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Jocelyn J Stooks
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Tyler B Baker
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | | | - Blair D Johnson
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Riana R Pryor
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - David P Basile
- School of Medicine, Indiana University, Indianapolis, Indiana
| | - Jacob C Monroe
- School of Medicine, Indiana University, Indianapolis, Indiana
| | - David Hostler
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Zachary J Schlader
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
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Deming NJ, Anna JL, Colon-Bonet BM, Dinenno FA, Richards JC. Carbohydrate ingestion attenuates cognitive dysfunction following long-duration exercise in the heat in humans. J Therm Biol 2021; 100:103026. [PMID: 34503773 DOI: 10.1016/j.jtherbio.2021.103026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/30/2022]
Abstract
INTRODUCTION To determine if electrolyte or carbohydrate supplementation vs. water would limit the magnitude of dehydration and decline in cognitive function in humans following long-duration hyperthermic-exercise. METHODS 24 subjects performed 3 visits of 2 h walking (3mph/7% grade) in an environmental chamber (33 °C/10% relative humidity). In random order, subjects consumed water (W), electrolytes (Gatorade Zero; E), or electrolytes+carbohydrates (Gatorade; E+C). Throughout exercise (EX), subjects carried a 23 kg pack and drank ad-libitum. Pre-and post-EX, body mass (BM) and plasma osmolality (pOsm) were measured. Physiological Strain Index (PSI) and core temperature (TC) were recorded every 15 min. Plasma glucose (GLU) was measured every 30 min. Cognitive processing (SCWT) was measured post-EX and compared to baseline (BL). A subset of 8 subjects performed a normothermic (N) protocol (21 °C/ambient humidity) to ascertain how the exercise stimulus influenced hydration status and cognition without heat. RESULTS There were no significant differences between fluid conditions (W, E, E+C) for BM loss (Δ2.5 ± 0.2, 2.5 ± 0.2, 2.3 ± 0.2 kg), fluid consumption (1.9 ± 0.2, 1.9 ± 0.2, 1.8 ± 0.2L), pOsm (Δ1.5 ± 2.7, 2.2 ± 2.4, 2.0 ± 1.5 mmol/L), peak-PSI (7.5 ± 0.4, 7.0 ± 0.6, 7.9 ± 0.5), and peak-TC (38.7 ± 0.1, 38.6 ± 0.2, 38.8 ± 0.2 °C). GLU decreased significantly in W and E, whereas it increased above BL in E+C at 60, 90, and 120 min (P < 0.05). Compared to BL values (43.6 ± 26 ms), SCWT performance significantly decreased in all conditions (463 ± 93, 422 ± 83, 140 ± 52 ms, P < 0.05). Importantly, compared to W and E, the impairment in SCWT was significantly attenuated in E+C (P < 0.05). As expected, when compared to the heat-stress protocol (W, E, E+C), N resulted in lower BM loss, fluid consumption, and peak-PSI (1.1 ± 0.1 kg, 1.2 ± 0.7L, 4.8, respectively), and improved SCWT performance. CONCLUSIONS These data are the first to suggest that, independent of supplementation variety, cognitive processing significantly decreases immediately following long-duration exercise in the heat in healthy humans. Compared to water and fluids supplemented with only electrolytes, fluids supplemented with carbohydrates significantly blunts this decrease in cognitive function.
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Affiliation(s)
- Nathan J Deming
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA; Air Force Institute of Technology, Wright-Patterson Air Force Base, OH, 45433, USA
| | - Jacob L Anna
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA
| | - Benjamin M Colon-Bonet
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80521, USA.
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Bodine SC, Brooks HL, Bunnett NW, Coller HA, Frey MR, Joe B, Kleyman TR, Lindsey ML, Marette A, Morty RE, Ramírez JM, Thomsen MB, Yosten GLC. An American Physiological Society cross-journal Call for Papers on "Inter-Organ Communication in Homeostasis and Disease". Am J Physiol Lung Cell Mol Physiol 2021; 321:L42-L49. [PMID: 34010064 PMCID: PMC8321848 DOI: 10.1152/ajplung.00209.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 12/17/2022] Open
Affiliation(s)
- Sue C Bodine
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Heddwen L Brooks
- Department of Physiology, University of Arizona College of Medicine, Tucson, Arizona
| | - Nigel W Bunnett
- Department of Molecular Pathobiology, New York University, New York, New York
| | - Hilary A Coller
- Molecular Biology Interdepartmental Program, University of California, Los Angeles, California
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California
- Department of Biological Chemistry, University of California, Los Angeles, California
| | - Mark R Frey
- The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, California
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Bina Joe
- Department of Physiology and Pharmacology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
- Center for Hypertension and Personalized Medicine, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Merry L Lindsey
- Department of Cellular and Integrative Physiology, Center for Heart and Vascular Research, University of Nebraska Medical Center, Omaha, Nebraska
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - André Marette
- Department of Medicine, Faculty of Medicine, Cardiology Axis of the Québec Heart and Lung Institute, Hôpital Laval, Laval University, Quebec City, Québec, Canada
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, Québec, Canada
| | - Rory E Morty
- Department of Translational Pulmonology and the Translational Lung Research Center Heidelberg, University Hospital Heidelberg, member of the German Center for Lung Research (DZL), Heidelberg, Germany
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center, Justus Liebig University Giessen, member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Jan-Marino Ramírez
- Department of Neurological Surgery, University of Washington Medical Center, Seattle, Washington
- Center on Human Development and Disability, University of Washington, Seattle, Washington
- Center for Integrative Brain Research at the Seattle Children's Research Institute, University of Washington, Seattle, Washington
| | - Morten B Thomsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gina L C Yosten
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, St. Louis, Missouri
- Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, Missouri
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Snopkowski RL, Vargas NT, Chapman CL, Johnson BD, Mietlicki-Baase EG, Temple JL, Schlader ZJ. The requirement for physical effort reduces voluntary cooling behavior during heat exposure in humans. Physiol Behav 2021; 232:113350. [PMID: 33548222 DOI: 10.1016/j.physbeh.2021.113350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 11/30/2022]
Abstract
We tested the hypothesis that cool-seeking behavior during heat exposure is attenuated when physical effort is required. Twelve healthy adults (mean(SD), 24(4) years, four women) underwent three experimental trials during two hours of exposure to 41(1) °C, 20(0)% relative humidity in which subjects undertook intermittent exercise alternating between seated rest and cycling exercise at ~4 metabolic equivalents every 15 min. In all trials, subjects wore a water perfused suit top. In the control trial (Control), no water perfused the suit. In the other trials, subjects were freely able to perfuse 2.1(0.2) °C water through the suit. In one cooling trial, subjects received two minutes of cooling by pressing a button (Button). The other cooling trial permitted cooling by engaging in isometric handgrip exercise at 15% of maximal grip strength (Handgrip), with cooling maintained throughout the duration the required force was produced or until two minutes elapsed. In both Button and Handgrip, a one-minute washout proceeded cooling. Core temperature increased over time in all trials (P<0.01) and there were no differences between trials (P = 0.32). Mean skin temperature at the end of heat exposure was lowest in Button [34.2(1.5) °C] compared to Handgrip [35.6(0.8) °C, P = 0.03] and Control [36.9(0.7) °C, P<0.01]. The total number of behaviors [8(3) vs. 10(5), P = 0.04] and cumulative cooling time [850(323) vs. 1230(616) seconds, P = 0.02] were lower in Handgrip compared to Button. These data indicate that when physical effort is required, the incidence and duration of cooling behavior during heat exposure is attenuated compared to when behaving requires minimal physical effort.
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Affiliation(s)
- Randi L Snopkowski
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Nicole T Vargas
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States; Thermal Ergonomics Laboratory, Discipline of Exercise and Sport Science, The University of Sydney, Sydney, NSW, Australia
| | - Christopher L Chapman
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States; Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Blair D Johnson
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States; Department of Kinesiology, School of Public Health, Indiana University, Bloomington, IN United States
| | - Elizabeth G Mietlicki-Baase
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Jennifer L Temple
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Zachary J Schlader
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States; Department of Kinesiology, School of Public Health, Indiana University, Bloomington, IN United States.
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Yosten GLC. AJP-Regulatory, Integrative and Comparative Physiology: Looking Toward the Future. Am J Physiol Regul Integr Comp Physiol 2020; 319:R82-R86. [DOI: 10.1152/ajpregu.00104.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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