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Caffeine is a naturally occurring substance that is widely consumed in a variety of forms. It produces multiple physiologic effects throughout the body. It is thought that this is mediated mainly through action at centrally located adenosine receptors. Caffeine has been studied for its potential use as an ergogenic aid. Several studies have demonstrated an improvement in exercise performance in submaximal endurance activities. Its potential ergogenic effect in acute, high-intensity exercise is less clear. Because of its potential use as an ergogenic aid, it use in sports is regulated by most sanctioning bodies.

(C) 2006 American College of Sports Medicine