A comparison of medium-term heat acclimation by post-exercise hot water immersion or exercise in the heat: adaptations, overreaching, and thyroid hormones.

This research compared thermal and perceptual adaptations, endurance capacity, and overreaching markers in men after 3, 6, and 12 days of post-exercise hot water immersion (HWI) or exercise heat acclimation (EHA) with a temperate exercise control (CON), and examined thyroid hormones as a mechanism for the reduction in resting and exercising core temperature () after HWI. HWI involved a treadmill run at 65% V̇o at 19°C followed by a 40°C bath. EHA and CON involved a work-matched treadmill run at 65% V̇o at 33°C or 19°C, respectively.

A comparison of heat acclimation by post-exercise hot water immersion and exercise in the heat.

Objectives: To compare heat acclimation adaptations after three and six days of either post-exercise hot water immersion (HWI) or exercise-heat-acclimation (EHA) in recreationally active individuals.

Design: Randomised, mixed model, repeated measures.

Methods: Post-exercise HWI involved a daily 40-min treadmill-run at 65% V̇O in temperate conditions (19 °C, 45% RH) followed by HWI (≤40 min, 40 °C water; n = 9).

Heat alleviation strategies for athletic performance: A review and practitioner guidelines.

International competition inevitably presents logistical challenges for athletes. Events such as the Tokyo 2020 Olympic Games require further consideration given historical climate data suggest athletes will experience significant heat stress. Given the expected climate, athletes face major challenges to health and performance.

Post-exercise Hot Water Immersion Elicits Heat Acclimation Adaptations That Are Retained for at Least Two Weeks.

Heat acclimation by post-exercise hot water immersion (HWI) on six consecutive days reduces thermal strain and improves exercise performance during heat stress. However, the retention of adaptations by this method remains unknown. Typically, adaptations to short-term, exercise-heat-acclimation (<7 heat exposures) decay rapidly and are lost within 2 weeks.

Post-exercise Hot Water Immersion Elicits Heat Acclimation Adaptations in Endurance Trained and Recreationally Active Individuals.

Hot water immersion (HWI) after exercise on 6 consecutive days in temperate conditions has been shown to provide heat acclimation adaptations in a recreationally active population. Endurance athletes experience frequent, sustained elevations in body temperature during training and competition; as a consequence, endurance athletes are considered to be partially heat acclimatized. It is therefore important to understand the extent to which endurance trained individuals may benefit from heat acclimation by post-exercise HWI.

Heat Acclimation by Postexercise Hot-Water Immersion: Reduction of Thermal Strain During Morning and Afternoon Exercise-Heat Stress After Morning Hot-Water Immersion.

Purpose: Recommendations state that to acquire the greatest benefit from heat-acclimation, the clock time of heat-acclimation sessions should match that of expected exercise-heat stress. It remains unknown if adaptations by postexercise hot-water immersion (HWI) demonstrate time-of-day-dependent adaptations. Thus, the authors examined whether adaptations following postexercise HWI completed in the morning were present during morning and afternoon exercise-heat stress.

Sauna exposure immediately prior to short-term heat acclimation accelerates phenotypic adaptation in females.

Objectives: Investigate whether a sauna exposure prior to short-term heat acclimation (HA) accelerates phenotypic adaptation in females.

Design: Randomised, repeated measures, cross-over trial.

Methods: Nine females performed two 5-d HA interventions (controlled hyperthermia T≥38.

Females exposed to 24 h of sleep deprivation do not experience greater physiological strain, but do perceive heat illness symptoms more severely, during exercise-heat stress.

There is limited and inconclusive evidence surrounding the physiological and perceptual responses to heat stress while sleep deprived, especially for females. This study aimed to quantify the effect of 24 h sleep deprivation on physiological strain and perceptual markers of heat-related illness in females. Nine females completed two 30-min heat stress tests (HST) separated by 48 h in 39°C, 41% relative humidity at a metabolic heat production of 10 W · kg.

Repeatability of a running heat tolerance test.

At present there is no standardised heat tolerance test (HTT) procedure adopting a running mode of exercise. Current HTTs may misdiagnose a runner's susceptibility to a hyperthermic state due to differences in exercise intensity. The current study aimed to establish the repeatability of a practical running test to evaluate individual's ability to tolerate exercise heat stress.

Isothermic and fixed intensity heat acclimation methods induce similar heat adaptation following short and long-term timescales.

Heat acclimation requires the interaction between hot environments and exercise to elicit thermoregulatory adaptations. Optimal synergism between these parameters is unknown. Common practise involves utilising a fixed workload model where exercise prescription is controlled and core temperature is uncontrolled, or an isothermic model where core temperature is controlled and work rate is manipulated to control core temperature.