Caffeine and running: should you hold down that cup of coffee until the race?

This is a tricky question. Should you drink coffee before a race or is a habit of drinking one or two coffees a day healthy? Does caffeine has an impact at all on your endurance?

The link between caffeine and running performance is complex and not fully understood. Here are some excerpts to help you determine if coffee should be part of your daily life (or not!).

For athletes, the common worry about caffeine is its diuretic effects and the common belief that caffeine can dehydrate you faster than you would wish for. In fact, in a review study from researcher at the University of Connecticut, it seems caffeine does not have an increased diuretic effect for athletes.

[T]here is no evidence to suggest that moderate caffeine intake (<456 mg) induces chronic dehydration or negatively affects exercise performance, temperature regulation, and circulatory strain in a hot environment.

The New York Times also reported about it.

But is caffeine good for you? In a rather lengthy review article, caffeine was found that have a positive impact on the metabolism of endurance runners.

Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also ben shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects.

Graham, T.E., Caffeine and Exercise: Metabolism, Endurance and Performance, Sports Medicine, Volume 31, Number 11, 1 November 2001, pp. 785-807(23).

Whatever you choose, it is important to be reminded that even though moderate consumption of caffeine can "increase alertness or ability to concentrate", too much caffeine will cause "insomnia, headaches, irritability and nervousness" (Health Canada).

My say on the subject: I'll keep on drinking those two cups of coffee a day!