Does aerobic exercise make you instantly smarter?


As of September 2017, new Sweat Science columns are being published at 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)


It’s old news that exercise is good for the brain. Dan Peterson of 80percentmental does a nice job of summing up some of the benefits here: increasing blood flow to the brain, making new brain cells, managing glucose. We usually think of that in terms of long-term benefits — stay active to avoid losing your marbles.

That’s why a forthcoming study (now available online) in Medicine & Science in Sports & Exercise caught my attention. Researchers from the University of Illinoise at Urbana-Champaign looked at the acute affects of a bout of exercise on cognition. Specifically, they measured the effect of aerobic and resistance training on working memory, by having their subjects memorize and recall series of random letters.

The punchline: 30 minutes of aerobic exercise improved working memory, both immediately after the workout and 30 minutes after. Resistance exercise (a typical weights workout for the seven major muscle groups, consisting of three sets of 8 to 12 reps at 80 percent of one-rep max) didn’t.

It’s too early to draw any serious conclusions (or make any jokes about muscle-heads) — but I have to admit, I’m surprised that someone could step off a treadmill and immediately perform better on a cognition test where the reaction times are measured in milliseconds. If nothing else, I figure my fingers would be too sweaty to press the button quickly enough. So, does this mean we should head out for a jog before big tests or important presentations?