Caffeine consumption prior to or during athletic training and competition has been the subject of great debate and confusion. Some experts seem to say it only hinders performance, while others say the opposite.

A March 2007 study by the Australian Institute of Sport (AIS) sought to provide comprehensive information and dispense with the confusion. The study returned some interesting results.

It’s well known that caffeine is a socially acceptable substance contained in popular drinks and coffee, as well as in some over-the-counter medications. According to the AIS, dietary sources (drinks, chocolate, etc.) typically contain 30 to 100 mg of caffeine per serving, while medications generally have 100 to 200 mg per tablet. Further, caffeine was removed from the World Anti-Doping Agency’s prohibited substance list in 2004, which allowed athletes to consume levels of caffeine consistent with their normal diet.

Contrary to widespread belief, the researchers found that any benefit of caffeine in endurance is likely short-lived, as not everyone responds in the same manner to the substance. Likewise, caffeine does not, as generally accepted, have a diuretic effect. Drinks containing caffeine can be a significant source of dietary fluid intake, and they do not aid in causing dehydration, particularly for habitual caffeine users.

Further, the AIS study states, “there is sound evidence that caffeine enhances endurance and provides a small but worthwhile enhancement of performance over a range of exercise protocols.” Whether a short-duration, high intensity event, or prolonged high intensity or endurance events, there is a clear benefit. The impact to strength events and short sprints is unclear. Although the benefit is clear, the source or reason for enhancement remains a bit of a mystery.

Athletes and general consumers of caffeine should, however, be careful. The benefits described occur with small to moderate levels of caffeine, take at a variety of times before, during and near the end of the activity; generally,70-150 mg of caffeine is an appropriate dose for most people. As a guide, a cup of coffee has between 40 to 110 mg of caffeine, and a typical can of cola contains around 40 mg.

Performance benefits do not increase with increased consumption of caffeine, in fact, quite the contrary. At higher levels of intake, caffeine has the potential to increase heart rate, impair fine motor control and cause over-arousal and interfere with sleep patterns, all of which can impair performance in a number of sports. Further, caffeine may adversely interact with other common supplements and there may be long-term problems with consuming large amounts of the substance. Researchers and many physicians recommend that the smallest effective dose be found.