In addition to providing energy, caffeine reduces the perception of fatigue. You can see why it’s popular with weight room warriors. But caffeine’s potential isn’t limited to strength training. A study published in the Journal of Science and Medicine in Sport looks at caffeine use by endurance athletes.

Researchers analyzed 40 peer-reviewed articles on placebo controlled trials during endurance races. They found that the effect size of caffeine’s performance enhancing benefits increases with the duration of the event.