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

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. Although 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 neighbourhood.

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.

How much of a boost can caffeine give?

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%, said Brad Schoenfeld, a professor of exercise science at the Lehman College in the New York City borough of the Bronx and director of the school’s human performance and fitness program. Although caffeine moderately improves anaerobic activities (intense, shorter workouts), such as weightlifting, sprinting and high-intensity interval training, it appears to show the most benefit with aerobic efforts (less-intense, longer exercises), such as 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 4 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 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 4 seconds,’ I’m going to take the supplement.”

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

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

How does it work?

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,” Guest said. This, in turn, releases other hormones such as 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,” 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 had been told they ingested caffeine. When the athletes were told they had been given a placebo, they ran more slowly, even if they had actually been given caffeine.

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

How should you use caffeine to help your 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,” Nelson said.

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

This article originally appeared in The New York Times.