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by Jani Sutherland

March 1, 2005

Some performance enhancement but watch side effects

In the eyes of the Olympic Committee caffeine has been a controlled or restricted  substance for many years. However, in 2004, the World Anti Doping Agency removed caffeine from its prohibited list. Before this change took place, more than 12 micrograms of caffeine per millimeter in your urine was considered illegal. To reach this prohibited level a person weighing 155 pounds would have to drink 5 to 6 cups of coffee (rapidly) right before competition. Those of us who sit around sipping espressos would never come close to that amount. Caffeine was always referred to as a potentially performance enhancing drug, which implied that high does of caffeine are needed to improve one’s performance.

Research has found that in well-trained athletes caffeine provides a small enhancement to exercise endurance. The amount of caffeine needed to affect performance is quite low, making higher amounts unnecessary. Lawrence Spriet, PhD., of the University of Guelph in Ontario, Canada, states: “The lowest dose reported to increase endurance during running and cycling is three milligrams per kilogram body mass or 210 mg for a 155 pound person when taken an hour before exercise.”

A strong cup of coffee (10-12 oz) could contain 210 mg of caffeine. Other caffeine sources include tea (8 oz provides 25-50 mg caffeine), 12 oz of cola (50mg) and chocolate (15-50 mg).  Some energy drinks can provide caffeine, up to 80 mg, and caffeinated gels can provide 20-50 mg. The amount of caffeine normally consumed in ones daily diet may be all that is needed to improve performance.

Recent data also indicated that as little as1-1.5 mg of caffeine per kg of body mass taken during exercise can improve performance. This date reinforces practices in cycling, running and triathlon of ingesting defizzed Coke. While not practical during pool meets it may have some benefit in long distance swimming. Currently no evidence exists that consuming higher amounts of caffeine (more than 1-1.5 mg per kg of body mass) before or during exercise provides more performance benefit. Prior research used very high levels of caffeine but athletes experienced adverse side affect with higher amounts. “Most people will feel little at 3 mg per kg if they do take caffeine sometimes, and more effects at 5 mg per kg, but side effects get problematic at 9 mg per kg body mass” says Spriet.

Side effects may include gastrointestinal disturbances, jitters, headaches, rapid heartbeat and sleep disturbances. Female athletes should also be aware that since they have higher estrogen levels than men, they probably do not metabolize caffeine as quickly  and ingestion will have a more prolonged impact.

In small amounts, caffeine poses no health advantages. The fact that caffeine is no longer on the banned list should help with the message that large amounts of caffeine provides no performance advantage. Say Spriet “The most important information is that caffeine will not work for everyone and must be tried before competition.”

And remember, the performance benefits of caffeine are not as high as the performance benefits of consuming fluid during exercise!

Reference: Monique Ryan, MS, RD.

This month's article, "Caffeine Revisited" is by USMS Fitness Committee Vice Chair Jani Sutherland. It was originally published in the Aqua-Master, newsletter of the Oregon LMSC, which was the recipient of the 2004 TYR / USMS Newsletter of the Year Award.


  • Health and Nutrition