Post-exercise hot water immersion induces heat acclimation and improves endurance exercise performance in the heat

We examined whether daily hot water immersion (HWI) after exercise in temperate conditions induces heat acclimation and improves endurance performance in temperate and hot conditions. Seventeen non‐heat‐acclimatized males performed a 6‐day intervention involving a daily treadmill run for 40 min at 65% V̇O2max in temperate conditions (18 °C) followed immediately by either HWI (N = 10; 40 °C) or thermoneutral (CON, N = 7; 34 °C) immersion for 40 min. Before and after the 6‐day intervention, participants performed a treadmill run for 40 min at 65% V̇O2max followed by a 5‐km treadmill time trial (TT) in temperate (18 °C, 40% humidity) and hot (33 °C, 40% humidity) conditions. HWI induced heat acclimation demonstrated by lower resting rectal temperature (Tre, mean, −0.27 °C, P