Short term heat acclimation reduces heat strain during a first, but not second, consecutive exercise-heat exposure
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, 120 min 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 120 min of moderate-high intensity treadmill exercise. Days 3-5 consisted of 90 min of moderate-high intensity exercise, with HOT completing this in a hyperthermia clamped manner at rectal temperature =38.5 °C, and CON < 38.5 °C.
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.
© Copyright 2021 Journal of Science and Medicine in Sport. Elsevier. Kaikki oikeudet pidätetään.
Aiheet: | suorituskyky harjoitusvaikutus ilmasto kuormitus palautuminen testi lämpötila adaptaatio urheilulääketiede termoregulaatio akklimatisaatio |
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Aihealueet: | valmennusoppi biologiset ja lääketieteelliset tieteet |
Tagging: | Hitze |
DOI: | 10.1016/j.jsams.2021.03.020 |
Julkaisussa: | Journal of Science and Medicine in Sport |
Julkaistu: |
2021
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Vuosikerta: | 24 |
Numero: | 8 |
Sivuja: | 768-773 |
Julkaisutyypit: | artikkeli |
Kieli: | englanti (kieli) |
Taso: | kehittynyt |