Regardless of the level of sporting activity, training and/or competing outdoors in hot conditions (air temperature >30-35°C) poses real challenges in terms of thermoregulation, hydration, and ultimately athletic performance. These conditions can, in extreme cases, have dramatic consequences if the intensity and/or duration of exercise is maintained. As climate change leads to an increase in heat exposure, it is essential to provide information and recommendations that will minimize the risks faced by athletes of all levels.

When possible, repeated exposure to heat stress (e.g., 60 to 90 minutes at 35-40°C and 40% relative humidity) for 7 to 14 days allows the body to acclimatize to the heat. Hydration also plays a key role in compensating for fluid loss (sweat, the amount of which increases in hot environments) that dissipates excess heat produced by the muscles. Similarly, the selection and use of cooling strategies (e.g., external (immersion in cold water), internal (cold drink or crushed ice), or combined application, administered before, during, or after exercise in hot conditions) allows for better physiological and psychocognitive tolerance and improved athletic performance.

Regardless of these measures, a number of recommendations should be adopted for athletes and any other participant, active or passive, in training or sports competition (officials, coaches, workers/volunteers and spectators), while providing for the restriction, postponement or cancellation of outdoor physical and sporting activities.