Myth Busters: Does Caffeine Work?

All serious athletes want to “work it harder, make it better, do it faster, make [themselves] stronger,” as the band Daft Punk so eloquently stated it. And that makes perfect sense! Of course they want to improve as much and as quickly as possible; otherwise there would be no point to training and working out regularly. But for many athletes, this quest for improvement can become all-consuming, and they turn to the use of supplements and medication to enhance performance even further. Drug and wellness companies make a fortune off of athletes looking for that extra “edge,” and there are myriad products out on the market today offering too-good-to-be-true promises. But do these supplements work? Well, that’s a difficult question to answer, but I’m going to tackle it piece by piece in my next few posts. Today I’ll start off the discussion with one of the most popular and widely used supplements out there: caffeine.As most of you are already aware, caffeine acts as a stimulant to oppose ones perception of fatigue. It is popular among college students cramming for finals, overworked employees, parents on the go, and many others. It’s in many common foods and beverages such as coffee, tea, chocolate, and soda, not to mention specialty energy drinks, gels, gummies, gum, or pills marketed toward athletes.

Does it improve exercise performance? The majority of studies indicate “YES!,” but as with most supplements, there are caveats to this rule. Caffeine supplementation has been shown to improve both endurance exercise and short-interval, high-intensity workouts (ex: running sprints), independent of training level. There are many possible reasons for this, but the most likely is that it blocks certain receptors in the brain, thereby decreasing perception of pain and effort during a workout. However, the drug has not been proven to enhance muscle strength, so it might not be as useful for power athletes (ex: weight lifting). Caffeine can be used in association with training sessions as well as competitions.

How much should I take? The recommended dose is about 3mg per kilogram of body weight for one bout of exercise, or about 200mg. For reference, an average cup of brewed coffee contains about 80mg of caffeine. (But it can vary a lot from one brand or style to another!)

photo: anthony_p_c via Flickr


  • Caffeine should be taken 45-60 minutes before the event.
  • If the event lasts longer than 1-2 hours (ex: marathon, Olympic or longer distance triathlon, biking race, etc.), take an addition 1mg/kg dose during the later stages of the event (or about 100mg).
  • Athletes should not take more than 5-6mg/kg as this may induce some negative side effects and likely won’t enhance exercise performance further.
  • If you are not a regular caffeine consumer, then increase your intake gradually to prevent possible side effects. An appropriate starting dose is 1mg/kg.
  • Some studies suggest that coffee is a less effective source of caffeine for exercise enhancements than other products, but the evidence is not conclusive. If you have a choice, consider alternate sources of caffeine.

Note: Every individual reacts differently to caffeine supplements, so be sure to test out a few different products or timing strategies to find out which one works best for you!

The Australian Institute provides a comprehensive list of caffeine-containing foods as well as some supplements found in various countries. Check it out here.

Are there harmful side effects?  At high doses (>6mg/kg), caffeine can cause insomnia, headache, gastrointestinal distress such as diarrhea or cramping, and dehydration (especially in hot weather). However, at moderate doses there are usually no negative side effects. Those who consume caffeine daily may also suffer some withdrawal symptoms if they suddenly eliminate their intake, so a gradual decline in intake is recommended.

Where/How can I get it?  Since caffeine is regularly consumed in “normal” foods, it is convenient and easy to find without having to search every local health or wellness store. See the link above for the AIS list of caffeine content in various foods.

Works Cited

Australian Sports Commission (2012, January). AIS Website Factsheet—AIS Sports Supplement Program: Caffeine [PDF]. Retrieved from: Australian Sports Institute

Maughan R.J., King D.S., & Lea T. (2004). Dietary Supplements. J Sports Sci, 22, 95-113.

Spriet, L. (2012, August 14). Caffeine: An Ergogenic Aid That Works! Lecture

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