Recovery
Heat Acclimation
Heat acclimation is the physiological adaptation process that occurs when athletes are repeatedly exposed to hot environmental conditions over a period of days to weeks. The body responds to sustained heat stress by expanding plasma volume, lowering the core temperature at which sweating begins, increasing sweat rate, and reducing the cardiovascular strain of working in the heat. These adaptations meaningfully improve exercise performance in hot conditions and reduce the risk of heat-related illness. With climate change extending the duration and intensity of heat exposure for outdoor athletes, heat acclimation has moved from a specialized Olympic sport concern to a practical priority for coaches working with any sport that trains or competes outdoors.
How it works
Adaptations begin within 3 to 5 days of heat exposure and are largely complete after 10 to 14 days of consistent sessions in the heat. The minimum effective dose appears to be 60 to 90 minutes of exercise per day at temperatures that elevate core body temperature above normal. Some coaches use passive heat exposure (sauna sessions after training) to accumulate heat stress without additional exercise load. Adaptations are specific to the conditions: acclimation to dry heat does not fully transfer to humid heat, and vice versa. Deacclimation begins within a week of returning to cool conditions.
Practical application
For teams preparing for preseason in hot conditions or competing in warm climates, a formal heat acclimation block of 10 to 14 days before the event is the most evidence-supported approach. For in-season management, awareness of wet-bulb globe temperature (WBGT) thresholds, adequate hydration protocols, and modified practice intensity during heat waves are the practical tools. Coaches should know the signs of heat exhaustion and exertional heat stroke and have a clear emergency action plan in place before any outdoor summer session.
Related terms
Load Management · Readiness Score · Wellness Questionnaire · Work Capacity