Nutritionists and athletic trainers have generally advised fasting from coffee and other caffeinated beverages before doing strenuous physical activity. Bruno Gualano, a physiology professor at the University of São Paulo who bikes a lot and drinks tons of coffee, put together a study that tested whether big-time coffee drinkers can get that energy boost without messing with their 12-cup-a-day habit. (The pangs of caffeine withdrawal are very real, after all.)
And according to his findings, it looks like they can. He broke a set of competitive male cyclists into three groups: a group whose caffeine intake was low (less than a cup of coffee per day), a group whose intake was moderate (about two cups), and a group whose intake was fairly high (three or more cups). He then had them perform time trials where they cycled as hard as they could until they burned 450 calories. They did it after taking a 400-milligram caffeine pill that was equal to about four cups of coffee, after taking a placebo, and after taking nothing at all — and almost every rider’s fastest trial was while on the caffeine pill. Their speed averaged 3.3 percent faster compared to no pill, and 2.2 percent faster compared to the placebo. In theory, the boost would translate to “several minutes” shaved off a marathon runner’s race time. Even crazier, the cyclists who were used to being extraordinarily well-caffeinated — slamming coffee and tea and Red Bull and whatever else every day — got the same boost as the people with little to no caffeine in their diets.
Naturally, Gualano warns that caffeine can also have dangerous side effects in large enough quantities, whether you’ve been abstaining for a few days or not. He recommends people start small if they want to see how this hack improves their physical performance. That means no beer-guzzler helmet of Death Wish coffee at your next 5K.