Tylenol’s pain-blocking boosts endurance performance


As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)


To the scientist in me, this is a really interesting study. But to the athlete and fan in me, it seems like bad news. British researchers fed highly trained cyclists acetominophen (Tylenol, as it’s known around here) before a 10-mile time trial. It was a double-blind, placebo-controlled trial. The riders who were fed Tylenol cycled about 2% faster, and had higher heart rate and lactate production (i.e. they were working harder) — but their perceived exertion was identical to the placebo group’s.

To read more about the study and its implications, read this entry in Amby Burfoot’s Peak Performance blog, which includes a Q&A with one of the researchers. The basic interpretation is simple: Tylenol blocks pain, and pain is what makes us slow down during long races. This is an important scientific result, because it sheds light on a red-hot debate about the nature and origins of fatigue. The authors of the study view their results as supporting the “central governor” theory, which argues that our brain subconsciously makes sure that we never let our body get too close to its absolute limits.

This, of course, is not the main message that many athletes will take from the study. A 2% performance boost is nothing to sneeze at for the well-trained athlete, so I expect that many athletes will start experimenting with Tylenol in training and racing. Is this dangerous? I don’t really know. (Gretchen Reynolds wrote an interesting article last summer about the risks athletes incur by overuse of NSAIDs like ibuprofen; Tylenol is a different class of drug.) But I have to admit: whenever I see a study of a potentially performance-enhancing pill, I cheer when the results come up negative, because (in my view) it keeps the sport a little simpler.

3 Replies to “Tylenol’s pain-blocking boosts endurance performance”

  1. I agree with you take that athletes will now start to ask about Tylenol supplementation. That will be the take away message they get. The fact that they were highly trained, working hard cyclists will go left unmentioned in the group ride discussions. 2% isn’t anything to joke about, but most the age group runners/triathletes I know have way more than 2% available through more consistent work within their training.

    No the science behind this is interesting. And the link they are trying to make to the central governor theory is something to think about?

  2. You have to wonder about the implications of this study. It seems to me that, as always, athletes will push the limits and try megadoses of tylenol.

    Similar to you, the scientists in me is excited about how this leads to an understanding of fatigue. The athlete in me is kind of scared.

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