Researchers show the absorption of carbohydrates increases when caffeine is added to sports drinks. This means an athlete will use energy from the drink rather than reaching into their own energy stores. And that, kinesiolgist Jim Pivarnik of Michigan State University, says will help endurance athletes play at a higher level without fatigue.
However, this study is just a starting point. The researchers did not look at how caffeine affects performance or if it can be harmful. Because caffeine is a diuretic, drinking too much before exercising for a long period of time, can lead to dehydration and other problems.
Experts do not suggest drinking high doses of caffeine before prolonged exercise until further studies, such as looking at these energy drinks' effect on the body's temperature, have been completed.