What Happened When I Replaced Coffee With 30 Seconds of Exercise

I've found that 30 seconds of high-intensity body-weight exercise gives me the same mental boost as a shot of caffeine. After validating the results of my newfound productivity hack on a Stanford-designed test of cognitive performance, these short breaks have become a staple of my workday.

Here's how it works, how I measured it, and some scientific theory to back up the findings.

Whenever I need a pick-me-up, I find a quiet corner and perform some form of body-weight exercise that jolts my heart up to at last 70 percent of the maximal beats per minute (for me, that's about 170). My favorite exercises are 20 burpees (a push-up to jumping jack) or 40 mountain climbers (push-up position, bringing knees to elbows).

Thirty seconds is a rough time frame; I actually go until I'm physically exhausted and feel my heart pounding through my chest. That's it.

How It's Measured

With the rise of scientific self-experimentation (a.k.a the "quantified self movement"), academics have designed measurement tools for committed amateurs. I compared my cognitive performance on caffeine and after exercise with quantified-mind.com, a website of reaction time and memory tests, which have been validated by decades of psychological research.

For instance, one test displays a series of nonsense symbols, each housed in a box labeled 1-9. When a larger version of the symbol displayed, I hit the corresponding number as quickly as possible. Mistakes count against the final score. Essentially, these types of games test if users are paying attention and if they can think on their feet (i.e. if I've got brain fog).

I compared my performance on this test to 250mg of caffeine. As seen from the graph below, my overall score increase 12 percent after exercise, compared to 6 percent on caffeine.

One more important note: on caffeine, my test for short-term memory was significantly higher on caffeine than exercise (26 percent vs. 16 percent). This jives with research that caffeine has a especially strong effect on sort-term memory.

The Science And Other Considerations

Coffee is a delightfully productive drug, but I'm not a fan of standing 20 minutes in line to spend $6 on an addictive substance that will eventually lose its cognitive benefits. Scientists have known for some time that exercise produces many of the same IQ-enhancing effects of a Starbucks.

Exercise and fitness are associated with better nourished portions of the brain that are responsible for higher-order thinking (PDF). To investigate how exercise makes us smarter, a 2012 meta-analysis from the University of North Carolina looked at all sorts of variables, from exercise duration to intensity and time-of-day.

The authors found that "very hard exercise" was almost twice as effective as "moderate" exercise. More importantly, exercise was only effective when it combined conditioning and strength training (like a burpee).

"The effects of acute exercise on cognitive performance are generally small; however, larger effects are possible for particular cognitive outcomes and when specific exercise parameters are used," concludes the team of researchers.

Will exercise work for you? Maybe. The researchers found that less fit people didn't benefit as much. My body is used to exercise and I get energized from it. For a couch potato, a pushup may require a nap and some therapy.