Skip to main content
Hamburger Menu Close



The secret to a better workout is probably already in your kitchen

Used correctly, caffeine can help you lift more, run faster and cycle farther.  

The secret to a better workout is probably already in your kitchen

While caffeine moderately improves anaerobic activities (intense, shorter workouts), like weight lifting, sprinting and high-intensity interval training, it appears to show the most benefit with aerobic efforts (less intense, longer exercises), like swimming, cycling and jogging. (Photo: Shawn Michael Jones for The New York Times)

For two years, Steph Gaudreau gave up her daily cup of coffee. She switched to large mugs of herbal tea — not because caffeine was affecting her sleep or making her anxious, but to gain an edge in cross-country mountain bike racing.

Hoping to enhance the effect of caffeine as a performance aid, Gaudreau, who lives in San Diego, drank a cup of coffee on race day as she warmed up. Once that prerace caffeine boost hit, Gaudreau, now a nutritional therapy practitioner and strength coach, said she felt a sense of euphoria, which helped her feel focused and mentally prepared for her race. The strategy paid off. In 2010, she took first place in a regional amateur biking race, called the Kenda Cup.

Caffeine is the most widely consumed psychoactive substance in the world and one of the best studied. Scientists have been looking at caffeine’s effect on athletics since the 1900s. While there is still some disagreement as to the exact mechanism by which caffeine consumption affects exercise performance, and whether taking a break from it until game day can give you an edge, scientists agree that a cup of coffee before working out can improve performance, whether you’re playing for the NBA or just running through your neighborhood.

However, it’s important to be aware of the potential downsides of caffeine consumption and to know how best to use it to your advantage when working out.


Gaudreau wasn’t imagining the effect of her prerace cup of coffee. There’s a good consensus among scientists that caffeine gives an exercising edge, whether it’s running a marathon, lifting weights or playing soccer, said Nanci Guest, a dietitian, coach and researcher at the University of Toronto who led a comprehensive review in 2021 of caffeine and exercise.

Whether consumed via coffee, a workout supplement or an energy drink, caffeine tends to improve performance by an average of 2 to 5 per cent, said Brad Schoenfeld, a professor of exercise science at the Lehman College in the Bronx and director of the school’s human performance and fitness program. While caffeine moderately improves anaerobic activities (intense, shorter workouts), like weight lifting, sprinting and high-intensity interval training, it appears to show the most benefit with aerobic efforts (less intense, longer exercises), like swimming, cycling and jogging.

For instance, a 2020 analysis of multiple studies about the effect of caffeine on rowing performance found that competitive rowers improved their time on a 2,000-meter row by about four seconds when using caffeine.

“It takes a lot of work to drop your 2,000-metre row, if you’ve been training for a couple of years,” said Mike T Nelson, an associate professor at the Carrick Institute for Clinical Neuroscience. “But if you said, ‘Hey, just take this supplement and we can decrease your time instantly by four seconds,’ I’m going to take the supplement.”

This response to caffeine varies from person to person, depending on factors like genetics, sex, hormonal activity and even diet. Some see performance improvement above 5 per cent, while others experience almost none.

“There’s fast metabolisers of caffeine and slow metabolizers of caffeine,” Dr Nelson said.


Caffeine’s influence on our nervous system starts with adenosine, a neurotransmitter that binds to specific receptors and makes us feel drowsy. Caffeine binds to those same receptors, blocking the adenosine from working.

“When caffeine blocks that receptor, the result is a stimulating effect,” Dr Guest said. This, in turn, releases other hormones like dopamine and epinephrine, which are related to mood, focus and alertness.

Some studies have shown that caffeine also helps our muscles produce more force. Our body needs calcium to initiate muscle contractions, and caffeine helps mobilize calcium ions so they have a greater interaction with the filaments that induce muscle fiber contractions.

“Caffeine enhances the ability for muscles to contract at a greater rate and thus would conceivably create greater power,” Dr Schoenfeld said.

Other studies show another powerful force at work: the placebo effect. If we expect caffeine to help us perform better, that may be enough. In one small study, competitive sprinters performed just as well with caffeine as they did with a placebo, as long as they’d been told they ingested caffeine. When the athletes were told they’d been given a placebo, they ran more slowly, even if they’d actually been given caffeine.

In other studies, like the rowing paper, experts do see improvements in performance over placebos, but not in measures like oxygen consumption, heart rate or how hard the workouts felt. The human body is extremely complex, Dr Schoenfeld said, and it’s often difficult to tease out the effect of one chemical on athletic performance.


Whether physical or mental, the benefits of caffeine apply to competitive athletes and those just wanting a slight improvement in their workout. One study found that caffeine improved the 5K times of well-trained runners by 11 seconds and recreational runners by 12 seconds.

“To the elite or high-level athlete, it’s going to mean a lot,” Dr Nelson said.

Studies show that the ideal performance-enhancing dose ranges between 1.4 to 2.7 milligrams per pound of body mass (though some research shows that even lower doses can work).

For instance, an eight-ounce cup of coffee has about 100 milligrams of caffeine, although this can vary depending on the type of coffee and the method of brewing. So, two cups of coffee for a 150-pound person comes out to 1.3 milligrams per pound. It may take some experimentation to find the right dose for you, because people metabolize caffeine differently. Whatever your ideal dosage, be sure to take it about an hour before exercise to allow time for your bloodstream to absorb the caffeine.

“The only thing I would say,” Dr Guest said, “is that somebody who’s not really executing a lot of energy, like they’re going for a walk, they would probably want to go with a lower dose, because when you’re stimulated, you need an outlet.”


While caffeine can help your exercise performance, it does have some adverse effects.

“If your performance involves fine motor skills, anecdotally those people tend to do worse,” Dr Nelson said.

If you drink coffee late in the day to help your evening workout, you may be disrupting your sleep.

“People underestimate the value of sleep,” Dr Guest said. Whatever performance gains caffeine is giving you could be nullified if you are experiencing chronic sleep deprivation. Caffeine also has other side effects for some people, including nervousness, anxiety and increased blood pressure.

If caffeine does worsen your sleep, she recommended taking it about eight to 12 hours before bedtime, depending how quickly your body metabolizes the chemical.

As for Gaudreau’s strategy of abstaining from caffeine to boost its performance-enhancing effects, a recent analysis of multiple studies found that habitual consumption doesn’t blunt caffeine’s performance-enhancing effects. You might experience a stronger placebo effect if you save your caffeine usage for before a competition. But Dr Guest also cautioned that the side effects of caffeine withdrawal, like headaches, fatigue and impaired concentration, could affect your training sessions, making you less prepared on game day.

For people who aren’t competitive athletes, the benefit of caffeine might be more about going to the gym than performing well there. After all, if your morning cup of coffee is what gets you out of bed, that might be all the performance enhancement you need.

Source: New York Times/hs