Exercise in the Heat. II. Critical Concepts in Rehydration, Exertional Heat Illnesses, and Maximizing Athletic Performance.

OBJECTIVE: To acquaint athletic trainers with the numerous interrelated components that must be considered when assisting athletes who exercise in hot environments. Useful guidelines to maximize performance and minimize detrimental health consequences are presented. DATA SOURCES: The databases MEDLINE and SPORT Discus were searched from 1980 to 1999, with the terms. "body cooling," "dehydration," "exercise," "heat illnesses," "heat," "fluid replacement," "acclimatization," "hydration," "rehydration," "performance," and "intravenous," among others. DATA SYNTHESIS: This paper provides an in-depth look at issues regarding physiologic and performance considerations related to rehydration, strategies to maximize rehydration, modes of rehydration, health consequences of exercise in the heat, heat acclimatization, body cooling techniques, and practice and competition modifications. CONCLUSIONS/RECOMMENDATIONS: Athletic trainers have a responsibility to ensure that athletes who exercise in hot environments are prepared to do so in an optimal manner and to act properly to avoid the potentially harmful heat illnesses that can result from exercise in the heat.