How Athletes Strategically Use Caffeine

Caffeine has become the performance-enhancing drug of choice in competitive sports. Using it in precise ways, and not excessively, seems most effective.

Andy Clark/Reuters

Every year, many of the planet’s fittest athletes converge in Kona, Hawaii, for the Ironman World Championship. It is a brutal triathlon: a 2.4-mile swim in the Pacific swells, followed by a 112-mile bike ride on a road flanked by lava fields, topped off by a marathon. You have to earn the privilege to race at Kona, and even that isn’t easy.

The 1,900 athletes competing in 2012 had taken the top few spots at qualifying triathlons all across the world. Most were jacked up on caffeine, the world’s most popular performance-enhancing drug.

Sarah Piampiano was among them. Though just a first-year pro, Piampiano had already won an Ironman race in New Orleans and was the second American woman at the 2012 Ironman U.S. Championship in Manhattan. The day before the Kona race, Piampiano was relaxing in a friend’s house, high above the endorphinated madness down in town, drinking a calorie-rich smoothie and telling me about her caffeine strategy.

Piampiano is not a caffeine addict. She has maybe two cups of coffee in a year, because she is sensitive to its effects. It makes her jittery. But on race day, she uses it thoughtfully and systematically to optimize her performance. She uses energy gels made by Clif Bar, one of her sponsors, to integrate calories and caffeine into her race-day nutrition plan. Before the race, she usually takes a gel with 50 milligrams of caffeine. Then on the biking leg, she takes 50 milligrams per hour. And that increases later in the race.

Piampiano uses Clif Shot Blocks, which are “kind of like gummy bears,” when it is easier to chew. She also has several energy gels—which have the consistency of thick honey and come in foil pouches—to use during the run. Throughout the day, she tries to take about 300 calories per hour and augments that with increasing doses of caffeine.

“As you get further into the marathon, your energy supplies are depleted and you just really start suffering; that’s why I start increasing the amount of caffeine I take. At the end of the marathon, you need that energy kick,” she said. And Piampiano said caffeine is an essential tool for an elite triathlete. “It’s critical, particularly if you want to perform and have any success at the top level.”

Like Piampiano, most of the super-fit endurance athletes at Kona used caffeine—but not everyone was on board.

Peter Vervoort, a physician from Belgium, has studied caffeine in athletes in Antwerp. He said for many athletes in his studies, doses of 200 to 350 milligrams were not helpful, especially in hot weather. He also competed in the Ironman and told me, “I’m not using caffeine. I do use Coca-Cola in the last 20 kilometers. But that’s caffeine in very small doses.” He said it’s actually getting hard to avoid caffeine on the race course. “There are more and more gel companies which only make gels with caffeine. So it is difficult.” Vervoort is an outlier. Most researchers have come to a different conclusion about caffeine’s ergogenic effects.

While in Kona, I tracked down Matthew Ganio, an exercise physiologist at the University of Arkansas Department of Health, Human Performance, and Recreation, and Evan Johnson, a University of Connecticut doctoral candidate. They have collaborated on caffeine research and were in Hawaii to study the effects of the triathlon on athletes’ physiology.

Ganio is soft-spoken but unequivocal about caffeine’s benefits for athletes. In 2009, Ganio and his colleagues published a systematic review of 21 studies on caffeine in timed performance. Most of the researchers looked at subjects cycling, but some also studied running, rowing, and cross-country skiing, and most of the tests were in the 15-minute to two-hour range. Looking across all the results, Ganio found consistent improvements in performance.

The improvements can be substantial, he told me, often as much as 3 percent. To put that into context, a 3 percent improvement would mean an 18-minute boost in a 10-hour race. Eighteen minutes was all that separated the top eight finishers in both the men’s and women’s pro races at Kona.

“There is always going to be some variability—some people won’t see as much of an effect as others; some people will see a large effect,” Ganio said. “Some people may not like it as much, or it may impair their performance a little bit. But on average, it does improve performance.”

For recreational athletes, too, the effects can be dramatic. A runner who is able to complete a 10K race in 40 minutes without caffeine could shave off 72 seconds with caffeine. And caffeine could allow a cyclist competing in a one-hour time trial to drop a minute and a half.

Ganio said it is important to take the right dose, which shakes out to about three to six milligrams per kilogram of body mass. That is a lot of caffeine. An 80-kilo (176-pound) athlete taking six milligrams per kilogram would need 480 milligrams of caffeine.

“That’s four strong cups of coffee,” said Ganio. “If you can tolerate it, it seems to be the upper end of what you can have to improve performance.”

Since “cups of coffee” is a notoriously imprecise measure of caffeine, it may help to think of it this way: 480 milligrams would be six 8-ounce Red Bulls, two and a half NoDoz tablets, or two Extra Strength 5-hour Energy shots. A more moderate dose for a smaller athlete, say, a 65-kilo (143-pound) athlete taking three milligrams per kilo, is still an impressive amount of caffeine: equal to one NoDoz tablet, one 5-hour Energy shot, or two and a half Red Bulls. Even this amount of caffeine is difficult to obtain using caffeinated sodas like Coca-Cola. A 65-kilo athlete would need to chug nearly six cans of Coke at once to get a caffeine dose of three milligrams per kilogram.

According to Ganio, endurance athletes have other misperceptions about caffeine. One of those is that it will dehydrate you.

One hydration study followed 59 healthy male volunteers for 11 days, using varying levels of caffeine. The researchers found no evidence of dehydration. “These findings question the widely accepted notion that caffeine consumption acts chronically as a diuretic,” the scientists concluded.

While this finding will seem counterintuitive to many coffee drinkers, especially commuters who have suffered through bladder-bursting traffic jams, Ganio said the science bears it out. Twelve ounces of coffee or 12 ounces of water will have about the same effect.

Evan Johnson, Ganio’s research colleague, explains that because individual reactions to the drug vary widely, caffeine is not for every athlete and best used judiciously.

“I have a little bit more of a public health overview of our use of caffeine in our nation,” he said. “You find a lot of people who constantly ingest caffeine throughout the day, and therefore at bedtime have trouble going to sleep; and then need alcohol or some sort of sleep aid to get to bed, and then in the morning are so groggy that they need caffeine again to get back into this kind of vicious cycle of supplementation. And I think when you get to that stage, it’s definitely a negative standpoint.”

While some athletic organizations such as the National Collegiate Athletic Association (NCAA), still limit caffeine—as they do other performance-enhancing substances—most now do not. Until 2004, the World Anti-Doping Agency and the International Olympic Committee considered 12 micrograms per milliliter in urine to be the maximum legal concentration. But they dropped caffeine from their list of prohibited substances in 2004 because caffeine is so ubiquitous that setting a threshold might lead athletes to be penalized for what others would consider normal caffeine consumption.

And for spectators who might be so inspired by the triathletes that they dust off an old 10-speed or lace up their running shoes? Caffeine helps them, too. A group of Australian researchers figured this out.

Their subjects were men who exercised less than an hour every week and did not regularly use much caffeine (less than 120 milligrams daily). They rode exercise bikes for 30 minutes, an hour after taking a gelatin capsule with either a placebo or a caffeine dose equivalent to 6 milligrams per kilogram. This is a hefty dose; the results were unequivocal.

“This study demonstrated that a moderate dose of caffeine improved cycling performance in sedentary men,” they reported. “Additionally, caffeine increased oxygen uptake and energy expenditure, without increased ratings of perceived exertion.”

In this case, it is the latter that’s more important. The men did not feel that they were working any harder, but they burned more energy, and this could “motivate previously sedentary individuals to become more active, which in turn has positive effects on aerobic fitness and overall health.”

But the researchers left off with one caveat: “Nonetheless, caffeine ingestion can be addictive with a variety of symptoms when withdrawal is attempted. Consequently, prescription of its use during exercise should be as a motivating tool during the initial stages of exercise only, particularly as the ergogenic effects of caffeine are partially diminished in habitual users.”

They concisely synopsized the challenges of using caffeine well: It can motivate you and improve your performance, but it is also addicting. In other words, use it to train, use it to race, but use it judiciously.

This post has been adapted from Murray Carpenter's Caffeinated: How Our Daily Habit Helps, Hurts, and Hooks Us.