Fresh coffee as soon as I step out of bed. A second cup during a mid-morning meeting. A 3 p.m. afternoon pick-me-up. I’m not alone when I say caffeine sets the pace of my day: Over 90 percent of Americans consume caffeine regularly, according to the United Brain Association.
But caffeine can do more than get us through the day with energy and without a pounding headache. We can use it for exercise, too, as it is “one of the very few dietary ingredients that has been researched and proven sufficient evidence to support its performance-enhancing effect,” says Jessie Anderson, MS, a board-certified specialist in sports dietetics at Top Nutrition Coaching. Ready to incorporate it? Keep scrolling.
How does caffeine help your workout?
Caffeine is a drug that stimulates the autonomic nervous system, specifically the sympathetic nervous system, which is “responsible for the fight or flight stress response,” says Marcos Anzures, a USA Track and Field Level 2-certified endurance coach and NSCA-certified strength and conditioning specialist. It increases heart rate, blood flow, respiration, adrenaline, and cognitive function, as well as improving metabolism and supporting muscle contraction.
These compounding effects enhance performance for nearly any workout. According to the International Society for Sports Nutrition, aerobic endurance can improve by two to four percent with caffeine consumption, and sprint and power output can jump by up to eight-and-a-half percent. It is particularly effective for prolonged efforts or high-intensity intervals because it mitigates pain during intense exercise by the dopamine release it provides.
“You’re able to go harder and longer,” says Anderson. That’s because it reduces our perceived exertion rate, making a workload feel easier even if your effort is the same. Resistance training and aerobic exercise also feel easier with caffeine because it delays what Anderson calls “central fatigue”—when your brain can no longer efficiently send signals to your muscles before they are actually tapped out. And it’s not only physical benefits; the focus and cognition benefits come in handy for skill-based sports where you need to problem-solve, react quickly, or formulate a game plan on the fly. Research shows that it increases passing accuracy for soccer players and increases the number of successful actions for volleyball players.
Another surprising effect? It can enhance recovery. “A small dose of caffeine, like a cup of coffee, actually accelerates glycogen replacement back into the muscle fibers,” says Anderson, which basically means that your muscles are being replenished with their energy source. To reap the benefits, you should add it to carbohydrate-rich beverages, like chocolate milk, according to a 2021 study.
How much caffeine do you need to boost your workouts?
When it comes to using caffeine for exercise, many people aren’t reaping the maximum benefits. According to a 2022 study, recreational athletes use lower caffeine amounts than what is established to enhance performance and consume it too close to exercise, not allowing sufficient time for absorption. So how do you—an already highly caffeinated being—start using it to enhance your performance? Tailor your approach and take out the guesswork.
First, consider your daily intake through all sources, like coffee (95 mg per cup), tea (25 to 50 mg per cup), energy drinks (80 to 300 mg), pre-workout and other supplements (150 to 300 mg), and even chocolate (12 mg per ounce). Anderson recommends “no more than 600 to 800 milligrams [or approximately six to eight cups of coffee] within a day and staying away from it at least six to eight hours before bedtime.” (However, it’s worth noting that the FDA considers 400 milligrams safe for healthy adults.)
Then, determine your dosage for your workout. The International Society of Sports Nutrition states that caffeine is effective when consumed in doses of three to six milligrams per kilogram of body weight, with the minimal effective dose as low as two milligrams. (This means about 600 milligrams for the median-sized U.S. male.) But ultimately, your ideal amount comes down to a number of factors, like your gender and tolerance. Anzures recommends starting at the lower end of the range to find the lowest dose that produces the desired effects and then adjusting that based on how your body reacts.
The timing of your caffeine intake is also important. Coffee and tea take about 60 minutes to kick in, whereas pre-workout powders or chewing gum get absorbed much faster, sometimes within 30 minutes. Over time, you’ll build up a tolerance, so if you want to use caffeine to enhance your performance before a race or competition, Anderson recommends tapering a week before, similar to how you would with the exercise itself. Then, start increasing your consumption a day or so before the race to see maximum benefits.
Okay, what are the drawbacks?
If all of this sounds too good to be true, I thought so too. My job is to be skeptical, so I really pried the experts to try to find substantial drawbacks to caffeine. Surely it has its limitations, right? Aren’t there sports it's not beneficial for? Isn’t it easy to take too much? Well, turns out, despite my digging, the drawbacks are relatively minimal, and it really is great for workouts.
Of course, there are a few things to keep in mind. The number one is sleep disturbance. Because caffeine has such a long half-life (the length of time it takes for your body to excrete half of the drug’s active substance), consuming it too late can cause restlessness and impact your sleep quality, which is proven to boost recovery. Another drawback is caffeine-use disorder, the overconsumption of caffeine to the point of psychological and physiological dependence, which affects eight percent of a study sample. “Caffeine is a well-researched drug, but the mantra ‘more is better’ does not hold true,” says Anzures. For some people who consume high doses, caffeine causes nervousness, anxiety, and gastrointestinal distress, which may take away from performance. Withdrawal symptoms of caffeine, like fatigue, depression, and difficulty concentrating, can also decrease your motivation to exercise.
For competing athletes, it’s important to note that caffeine supplements are not regulated, so proceed with caution. “This is especially true if they are an athlete whose sport is governed by anti-doping regulations,” says Anzures. “Supplements are notorious for containing substances not listed.” If you want to use supplements instead of natural sources of caffeine, like coffee and tea, you should look for products that have an NSF certification, says Anderson, which ensures that they meet rigid third-party testing criteria.
And when in doubt: Drink caffeine. Not too much. Mostly coffee.
