Does consuming caffeine before exercise help or hinder your performance? The verdict is in.

Earlier this year, the International Society of Sports Nutrition (ISSN) published their official report on how caffeine affects exercise performance. They evaluated all of the available literature on the subject of caffeine and exercise, analyzing information from 420 different articles.

Here are key takeaways from the ISSN’s report:

Yes! Caffeine improves aerobic endurance.

Dozens of studies show that caffeine consistently improves endurance by 2-4%. That might sound like a small improvement, but it can make a big difference. According to the ISSN, “less than a 1% change in average speed is enough to affect medal rankings in intense Olympic endurance events.” A perfectly timed caffeine boost could be the difference between silver and gold.

Ok, great, but most of us are not Olympic athletes. Don’t sweat it. The ISSN reports that caffeine improves physical performance no matter what level of training you’re at. Even the most casual gym goer benefits from a caffeine buzz.

The optimal time to take caffeine depends on the method of consumption.

How do you take your caffeine? Most people get their caffeine from coffee, soda, or tea, but some athletes choose to supplement with caffeine gum or capsules. The method of consumption determines how quickly caffeine is absorbed into the bloodstream, and therefore, when it will have the maximum effect on physical performance. One of the studies the ISSN included in their report found that coffee and tea drinkers typically experience peak caffeine plasma concentration (maximum caffeine in the bloodstream) after roughly 30 minutes. Caffeine from soda takes a lot longer to be absorbed, approximately 2 hours.

The exact time it takes for caffeine to be absorbed differs from person to person, and the clinical  studies reflect this same variability. However, the researchers note that caffeine chewing gum is always absorbed the fastest by a significant margin. If you’re looking for an immediate jolt, gum is the way to go. Caffeine capsules take significantly longer, approximately an hour.

The most common time to take caffeine is 60 minutes before exercise.

Consuming caffeine 60 minutes before exercise is most common because it’s a pretty safe bet. An hour is typically enough time for caffeine to be absorbed into the bloodstream, meaning plasma levels of caffeine will be at maximal values. But the ISSN also reports that caffeine may actually be most beneficial when ingested during exercise.

For longer endurance events, such as a marathon or triathlon, caffeine seems to help the most when you’re already tired. Numerous studies found that taking caffeine during the mid/late stages of a long race or lengthy workout improved performance more than when caffeine was ingested beforehand.

Everyone reacts a little differently to caffeine and exercise.

Of course, what works well for one person may not produce the same results for someone else. The ISSN reports that “there appears to be substantial interindividual variability in response to caffeine under exercise conditions” which could be attributed to factors like genetics, anxiety, and habitual caffeine intake.

Caffeine is also commonly associated with side effects such as headaches, difficulty sleeping, and anxiety—so always use it carefully. If you are planning to incorporate caffeine into your exercise regimen, start slow and experiment with the method, timing, and dosage. Just like most things in life, it is most important to find what works best for you.  

For more information on potential side effects of caffeine, check out Healbright’s Caffeine and Mental Health content featuring Dr. Cheri King on Zeamo On-Demand.