Dehydration, Hyperhydration, and Hyponatremia in Tropical Climates

Summary. Six statements are presented with supporting data: (1) An important number of athletes train and compete in hot and humid conditions that impair their performance; (2) dehydration should be avoided when exercising in the heat; (3) many athletes arrive hypohydrated for their workouts or competitions; (4) complete rehydration is possible for some individuals; (5) quick post-exercise rehydration remains a challenge; and (6) exercise-associated hyponatremia is not likely to happen in the heat. Exercise in the heat. This presentation is one of several topics related to exercise in the heat. In this context, it is important to start by understanding just how hot are the environmental conditions that athletes may face while competing and training in a tropical climate. The most widely used environmental heat stress index is the Wet Bulb Globe Temperature (WBGT). WBGT is a weighted average of dry bulb temperature (T db ), wet bulb temperature –which is sensitive to relative humidity and to wind speed (T