In the crowded world of overhyped and ineffective sports supplements, caffeine stands out because, well, it works. Study after study has confirmed that it boosts endurance performance, for reasons that are probably related to changes in how you perceive effort. But caffeine stands out for a different reason, too: Most people already consume it regularly. As with any other drug, you build up a tolerance to caffeine’s effects with repeated use, making a given dose less effective. As a result, a common practice among elite athletes is to swear off coffee and other caffeine sources for up to a week before a big race, in order to ensure they get the maximum jolt from their pre-race caffeine.
Is this really necessary? In a new study reported in the Journal of Applied Physiology, Brazilian scientists asked 40 cyclists to complete a series of 30-minute all-out trials, with or without caffeine. Sure enough, the cyclists were 2.5 per cent faster with caffeine than with a seemingly identical placebo.
But the key result came when they divided their subjects into low, medium or high-caffeine users based on their habitual consumption. There was no difference between the three groups in the size of the boost they got during their caffeinated ride. That suggests that whatever tolerance the high-caffeine group may have built up, it didn’t affect the endurance benefits – so, to the relief of spouses and children everywhere, there’s no need to swear off caffeine (and incur the unpleasant effects of withdrawal) before a big race.