Race Fueling

Caffeine for Triathlon Performance: How Little Is Enough?

A new study may help triathletes benefit from caffeine without overdoing it.

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A new study may help triathletes benefit from caffeine without overdoing it.

Photo: Robert Murphy

Caffeine is classified as a restricted substance by the International Olympic Committee, the United States Olympic Committee, and the NCAA. This means that athletes who compete under the jurisdiction of one of these governing bodies are allowed to have caffeine in their system when they compete, as long as they don’t have too much. Collegiate and Olympic athletes are thus incentivized to consume the smallest amount of caffeine prior to competition that is sufficient to attain the maximum possible enhancement of performance.

Even those of us who are not required to urinate into a cup after races would be well advised to aim for the same balance. Even though there is no maximum legal caffeine limit for age-group triathletes, caffeine is still a drug regardless of who’s taking it, so it’s wise not to risk overdoing it. Excessive caffeine intake may cause increased heart rate, tremors, and stomach upset. Like our elite counterparts, we therefore want to consume the least amount of caffeine that will do the job in races (or avoid it altogether).

RELATED: The Pros And Cons To Caffeine-Infused Training And Racing

Researchers at Australia’s Griffith University recently made an effort to pin down this optimal number. Past research has suggested that a dose of 2 mg of caffeine per kg of bodyweight before competition is the minimum amount required to produce an enhancement of performance. A dose three times larger—6 mg/kg—is believed to represent the ceiling of benefit. If you take any more than that, you’ll get no additional performance enhancement. The Griffith University team sought to determine whether a dose of 3 mg/kg would yield less performance benefit than 6 mg/kg or just as much.

Sixteen well-trained male cyclists participated in the study. Each of them performed a time trial on a stationary bike that took a little less than an hour to complete in the average case. The test was repeated on three separate occasions. Before one time trial the cyclists received 3 mg of caffeine per kg of bodyweight. (Thus, a 150-lb rider would have received 204 mg of caffeine, or just a hair more than the amount contained in a single No-Doz tablet.) Before a second trial the subjects received 6 mg of caffeine per kg of bodyweight, or slightly more than the amount of caffeine that is contained in a grande cup of Starbucks coffee, in the case of our 150-lb rider. Before the remaining time trial the subjects received a placebo pill. The order of the treatments was randomized.

The results? The time it took the cyclists to complete the time trial was reduced by 4.2 percent with the lower dose of caffeine compared to the caffeine-free condition. Performance was actually improved somewhat less—by 2.9 percent—following the larger dose of caffeine. The difference between the two caffeine conditions was not statistically significant, however. This means that if the whole experiment were repeated, it would be just as likely that 6 mg/kg of caffeine improved performance by 4.2 percent and 3 mg/kg by 2.9 percent.

RELATED: Is It Necessary To Withdraw From Daily Coffee?

The most important revelation of this experiment is that a relatively modest dose of caffeine is sufficient to maximize the performance benefits of caffeine. Regular coffee drinkers consume caffeine in amounts roughly equal to 6 mg/kg before exercise all the time. Such athletes may or may not be concerned about ingesting an the same amount before races. Non-habitual caffeine users and anyone else who is concerned about overdoing caffeine can now rest assured that 3 mg/kg will do the trick. And, of course, avoiding caffeine altogether before races is always an option too.


Matt Fitzgerald is the author of Iron War: Dave Scott, Mark Allen & The Greatest Race Ever Run (VeloPress 2011) and a Coach and Training Intelligence Specialist for PEAR Sports. Find out more at Mattfizgerald.org.