Caffeine and Athletic Performance
2025 Old Glory Ultra Relay runner Zach Polega.
If you’re one of the 90% of adults who use caffeine to get through the day, then you might also be one of the many who use it for performance. Caffeine is one of the most widely researched ergogenic aids and the research on whether it will help your performance is clear. It can give you an edge.
How Does It Work?
While most adults consume their caffeine in the form of a favorite dark morning beverage, you’ll also get it in tea, soda, energy drinks, chocolate, functional beverages, and supplements. In fact, it’s a little trendy right now, so you might find it in unexpected foods, like yogurt and water.
Whether it’s naturally occurring or from a supplement, caffeine works in the same way. Caffeine blocks the action of adenosine, a substance that helps regulate our sleep. Caffeine has a similar molecular structure to adenosine and binds to the receptors, which turns it off—this results in being more alert, focused, and can increase energy, all needed for exercise performance. It may also reduce perceptions of effort and pain.
Using caffeine as an ergogenic aid works best to improve endurance/aerobic exercise and strength training, and may improve high-intensity exercise and performance during team sports.
Caffeine benefits performance in trained and untrained people, but the effect of caffeine on performance is dependent on an individual’s caffeine response and tolerance.
The Ideal Amount of Caffeine for Optimal Performance
As with many recommendations in sports nutrition, it’s personal. The minimum effective dose is as low as 2mg/kg of body weight, but the sweet spot lies somewhere between 3 and 6 mg/kg of body weight. Using caffeine above this amount will give you more side effects than performance benefits.
To put those amounts into context, a soda has 30-40 mg of caffeine and a cup of brewed coffee has around 80 to 100 mg of caffeine.
For a 150-pound person, 204 mg of caffeine would be 3 mg/kg of body weight, which is appropriate for performance benefits and equivalent to about 2 cups of coffee.
Will Caffeine Work For You?
You won’t know until you try. The effects of caffeine typically kick in within 30-45 minutes.
However, if you are a slow responder, it can take longer. Caffeine stays in your body for about 5 hours, which is part of why you feel the dreaded “afternoon slump” and often need a pick-me-up.
The response to caffeine is individualized, but so are the side effects. If you are sensitive to higher amounts of caffeine, it’s possible to have any or all of the following:
Jitters
Heart palpitations
Mental confusion
Gastrointestinal discomfort
Nervousness
Sleep Issues
Caffeine is a diuretic and can lead to increased urination, especially for those who are sensitive to its effects. However, for most individuals, caffeine at low or moderate levels does not significantly affect hydration status.
Best Practices
If you want to utilize the ergogenic benefits of caffeine for your next long run, workout, or training session, it’s best to start on the low end and evaluate how you feel. If you generally consume caffeine, whether it’s your morning cup of coffee or tea, you most likely have a small tolerance already built up.
Do the math above and pay attention to how much caffeine you are already consuming. Pre-workouts, energy drinks and gums can have surprisingly high amounts of caffeine, so read labels.
Packaging should indicate how much caffeine is in your product, but it might come from different sources. Synthetic caffeine may be labeled as caffeine anhydrous, while natural sources of caffeine can be many sources, such as green coffee bean extract, green tea extract, or guarana.
Lastly, using caffeine for performance should be strategic and purposeful. As with many other performance supplements, high doses can be dangerous, even fatal. In addition, caffeine can interact with some medications, such as antidepressants, so it’s best to avoid or talk to your healthcare team if you want to supplement with caffeine for performance benefits and you take medication.
Bottom Line
Caffeine, when used responsibly, can improve athletic performance. Whether from coffee or a pre-workout supplement, there are advantages and risks. Evaluate your current caffeine intake and, if supplementing, start with the lowest effective dose to mitigate side effects.
Sarah Pflugradt is a registered dietitian with a specialization in human performance. She is an Air Force vet, a military spouse, and a health promotion professor at American University in Washington D.C. She spends her free time cooking, writing, and watching her 3 kids compete in sports.
