DEHYDRATION, ITS EFFECTS ON PERFORMANCE, AND ITS RELATIONSHIP TO HEAT ILLNESS:

Appropriate hydration before, during, and after physical activity is an important ingredient to healthy and successful sports participation. Weight loss during exercise and other physical activity represents primarily a loss of body water. A loss of just 1 to 2 % of body weight (1.5 to 3 pounds for a 150-pound athlete) can negatively impact performance. A loss of 3 % or more of body weight can significantly increase the risk for exertional heat-related illness. If an athlete is already dehydrated prior to beginning activity, these effects will occur even sooner. Athletes should be weighed (in shorts and T-shirt) before and after warm or hot weather practice sessions and contests to assess their hydration status. Athletes with high body fat percentages can become significantly dehydrated and over-heat faster than athletes with lower body fat percentages while working out under the same environmental conditions. Athletes have different sweating rates and some lose much more salt through their sweat than others. “Salty sweaters ” will often have noticeable salt stains on clothing after workouts, and often have a higher risk of developing exertional muscle cramps