Sound Science: Caffeine and Athletic Performance

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Whether you run on caffeine or caffeinate up before your run, here’s a bit of good news to jump start your day.

In a study published in the International Journal of Sport Nutrition and Exercise Metabolism, researchers from Dublin City University found that caffeine consumption before high-intensity aerobic activity may improve athletic performance under certain circumstances.


The goal of the study was to determine a correlation between the intake of caffeine and high-intensity aerobic performance in the 40-meter maximum shuttle run test. The shuttle run consists of a series of 10 40-meter sprints with 30 seconds allotted to each round. Repeated sprint performance (RSP) was measured by the sprint decrement percentage, or the decrease in average performance of all laps when compared to a participant’s best sprint in each trial.

Eighteen participants were recruited from a pool of male athletes from multiple team sports. Each participant ran the test a total of four times: twice to familiarize themselves with the methodology, once after ingesting 200 mg of caffeine via a piece of gum and once after ingesting a placebo.

While researchers were not able initially to link caffeine consumption to improved RSP across the board, they did discover that 10 of the 18 participants received a statistically significant increase in performance when compared to their more heavily caffeinated counterparts (>130 mg/day). It is important to note that these 10 participants were not heavy caffeine consumers, consuming less than 40mg/day. These results suggest that frequent use could decrease a person’s sensitivity to caffeine and thus dull its energy-boosting effects come performance time. If you’re looking to gain the greatest edge from caffeine supplementation, it might be a good idea to cut back on your daily coffee and tea intake in the weeks leading up to a competition.

Strengths and Limitations:

As with any study, it is important to recognize the strengths and limitations in order to direct future research and fill the gaps in knowledge. The DCU investigators utilized a randomized, double-blind, placebo-controlled study design in order to minimize confounding variables. In addition, the team chose to assess aerobic performance with a modified version of the original shuttle run, developed by Leger et al. in the 1980s and validated in a multitude of studies ever since.

However, it’s difficult to draw concrete conclusions from such a small sample size of 18, further decreased when stratified into light- and heavy-caffeine consumers. Moreover, the participants potentially introduced recall bias into the study when quantifying their own caffeine consumption habits.

Caffeine in Perspective:

While caffeine isn’t a magic bullet that will catapult your athletic abilities into the stratosphere, current research is promising in its potential as a performance-enhancing aid, especially in those who aren’t habitual coffee fiends. That’s in addition to a host of other previously discussed benefits including decreasing inflammation and even protecting against chronic diseases.

As with all things, moderation is key. Check out our caffeine fact sheet for more information on how much caffeine you should consume and the amount of caffeine in different products.

This blog post was written by David Hu, RD.