Caffeine and Its Effects on Exercise Performance
It’s the end of a long and trying workday. You want couch, and plenty of it. But on the way home you knock back a double espresso and find, miraculously, on arrival you’re ready for that round of INSANITY MAX:30 you’d planned to blow off.
Ah caffeine, the original performance-enhancing drug.
Caffeine is the most widely used psychoactive substance in the world. According to the Centre for Addiction and Mental Health (CAMH), more than 80 percent of North American adults regularly consume caffeine, with intakes averaging between 210 and 238 mg per day. One in 10 of us ingests 1000 mg per day or more, from sources that include coffee, cola, tea, sports drinks, chocolate, and non-prescription supplements.
Yet despite caffeine’s ubiquity — and considerable research on the topic — its role in athletics is still emerging science. People of all stripes consume caffeine to enhance their well-being and daily activities, but athletes are often left wondering how it affects their performance, notes Louise Burke, head of Sports Nutrition at the Australian Sports Commission and co-author of Caffeine for Sports Performance.
And it’s not as if the beverage industry has played down the potential link between caffeine and athletic performance. As far back as 1928, Coca-Cola sent 1,000 cases with the U.S Olympic team to the Amsterdam games, and Coke remains the Olympics’ longest continuous corporate sponsor.
Until recently, caffeine was considered a banned substance by the World Anti-Doping Agency (WADA). Burke says that when it’s intentional, athletes usually used caffeine to reduce fatigue or offset a performance decline that would otherwise occur during an event. But given how prevalent caffeine is, some athletes were “juicing” without even realizing it. “Not all athletes who have caffeine in their system while they train or compete had the intention of gaining a performance advantage,” Burke says. Recognizing this, WADA removed caffeine from its list of prohibited substances in 2004. The National Collegiate Athletics Association (NCAA) still considers it a regulated, but not banned, substance.
How Caffeine Can Give Your Workouts a Jolt
The stuff works, as any swing-shift employee can attest, and used judiciously can help both get your butt out there on training days, and peak your performance in competition.
At the physiological level, ingested caffeine is quickly absorbed by the stomach and peaks in the blood within 1-2 hours. Initial effects — the jolt — can be felt sooner, and women metabolize caffeine about 20 percent quicker than men.
Because caffeine is absorbed by most human tissue, it can affect all of the body’s major systems. Caffeine stimulates your brain, can elevate your mood, and postpones fatigue. While it doesn’t appear to improve fine motor coordination, it has been shown to improve endurance and performance at simple tasks.
Studies in the 1970s suggested that caffeine helped performance in endurance exercises by upping the level of adrenaline in the blood, which in turn stimulated the release of free fatty acids from fat tissue or skeletal muscle. The idea was that working muscles were using this as an energy source early in the exercise, saving more glycogen for later on.
And there’s probably something to that, according to the American College of Sports Medicine. While conflicting studies in the 1980s left many thinking caffeine had no real net impact on athletic performance, more recent double-blind experiments have found there is a physical gain to be had. For some. At certain concentrations.
Are there any downsides to caffeine? Well, shaky hands are a telltale sign of too much of the stuff. (This is a problem easily solved for most by sticking to low doses.) And if you consume caffeine before bedtime, you’ll probably take longer to fall asleep and sleep less deeply. Happily, the wives’ tale that caffeine is a diuretic has proven false under study: Not only do you not pee more than if you were drinking plain water, you also don’t lose substantially more moisture due to sweat.
How Much Caffeine Is Ideal?
In a well-regarded 2002 study, researchers examined how competitive cyclists performed using caffeine vs. a non-caffeinated but otherwise nutritionally-sound sports drink under two protocols. In the first, they tested how subjects performed in time trials using varying levels of caffeine before or during a ride. In the second, they gave subjects Coca-Cola in the final 40 minutes of a long, steady-state ride. Between the two studies, it was determined that 6 mg/kg of body mass did have an ergogenic effect.
A 2012 study compared that amount to 3 mg/kg of body mass and uncovered that the lower dose was equally as effective. While this research was on cyclists, it’s been shown that caffeine taken before exercise can help across a range of sports, including endurance events like long-distance running, stop-and-go events like racquetball, and sports involving sustained high-intensity activity lasting up to an hour, such as swimming and rowing.
But the benefit may go beyond just the physical. “Performance is not all physiological — a lot of it is mental,” notes Bob Girandola, an associate professor of Biological Sciences at USC who has taught classes on drugs in sports.
“Caffeine may affect your subjective feeling of fatigue or stress or pain,” Girandol says. “If you and I were doing an exercise and I was taking caffeine and you were not, perhaps it would feel a little bit less strenuous to me.” He explains that over the course of a sustained training regimen that could provide an advantage. “With any kind of performance enhancing substances, there’s a lot of individual variation with people. I always tell athletes here, as long as it’s not illegal…take it during practice and see if you think it’s going to help. Even if it’s just psychological, that’s fine.”
