Short term heat acclimation reduces heat strain during a first, but not second, consecutive exercise-heat exposure
| Autor: | Douglas J Casa, Lesley W. Vandermark, J. Luke Pryor, Carl M. Maresh, Elaine C. Lee, Riana R. Pryor, Elizabeth L. Adams, Rachel M. Brodeur, Lawrence E. Armstrong |
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| Rok vydání: | 2020 |
| Předmět: |
Hyperthermia
Male Hot Temperature Time Factors Acclimatization Physical Therapy Sports Therapy and Rehabilitation Treadmill exercise Sweating Body Temperature 03 medical and health sciences Young Adult 0302 clinical medicine Animal science Heat acclimation Heart Rate Heart rate Medicine Humans Orthopedics and Sports Medicine 030212 general & internal medicine Cardiovascular strain Exercise business.industry Rectal temperature Humidity 030229 sport sciences medicine.disease business Skin Temperature Heat-Shock Response |
| Zdroj: | Journal of science and medicine in sport. 24(8) |
| ISSN: | 1878-1861 |
| Popis: | Objectives Determine whether five days of heat acclimation reduces cardiovascular and thermoregulatory strain during consecutive exercise-heat exposures on the sixth day in the heat. Design Pair-matched randomized control trial. Methods Twenty-four males completed two, 120min exercise sessions (Session 1, Session 2) in a single day before (Day 1) and after (Day 6) four additional days of exercise in either hot (HOT: 40°C, 40% relative humidity, n=16) or temperate (CON: 23°C, 25% relative humidity, n=8) environments. A mixed-methods heat acclimation approach was implemented. Day 2 consisted of 120min of moderate-high intensity treadmill exercise. Days 3-5 consisted of 90min of moderate-high intensity exercise, with HOT completing this in a hyperthermia clamped manner at rectal temperature ≥38.5°C, and CON Results Session 1 end of exercise rectal temperature and heart rate were lower on Day 6 compared to Day 1 for HOT (p=0.012, p=0.003) but not CON (p=0.152, p=0.437). Session 2 end of exercise rectal temperature was not different between days for HOT (p=0.104) or CON (p=0.275). Session 2 end of exercise heart rate was lower on Day 6 compared to Day 1 for HOT (p=0.004) and CON (p=0.039). Session 1 sweat sensitivity was greater on Day 6 compared to Day 1 for HOT (p=0.039) but not CON (p=0.257). Sweat rate was unchanged for HOT and CON between days during Session 1 (p=0.184, p=0.962) and Session 2 (p=0.051, p=0.793), respectively. Conclusions Five days of heat acclimation reduced cardiovascular strain but not thermoregulatory strain during the second, consecutive exercise-heat exposure. CLINICALTRIALS. Gov identifier NCT04053465. |
| Databáze: | OpenAIRE |
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