To Exercise More, Sleep More First

Sleep and exercise have a chicken-or-the-egg sort of relationship. Evidence exists that exercise can improve sleep, and also that sleep may improve exercise. But which one happens first? Does sleep improve exercise, or exercise improve sleep? This remained a tough egg to crack.

To investigate this “bidirectional relationship,” researchers publishing in the Journal of Clinical Sleep Medicine recruited 11 women suffering from insomnia to report back on all of their sleeping and exercising for 16 weeks. The women were instructed to exercise for at least 30 minutes per day, three days per week. The researchers also asked their subjects to wear special wrist bands, which recorded physical readings about their sleep quality and quantity.

The results turned out to be a bit counterintuitive. ”Results suggest that sleep influences next day exercise rather than exercise influencing sleep,” the researchers conclude in their paper. “These results suggest that improving sleep may encourage exercise participation.”

Scicurious further explains, writing for Scientific American:

The authors found that working out did NOT immediately affect your next night’s sleep, though after 16 weeks of the study, people slept about an hour more per night than they had before. But on any given night, whether you worked out didn’t affect how well you slept. But instead, how much you slept the night before predicted how much exercise you got the next day.

The more sleep the women got, the more exercise they managed to pull off the next day, the researchers found. Exercise, in other words, is not a quick fix for sleeplessness. While banking hours at the gym can eventually improve sleep, sleeping pills, unfortunately, remain the best option for a quick trip to the Land of Nod, Scicurious writes.

More from Smithsonian.com:

Too Little Sleep Can Really Mess Our Bodies Up
Better Sleep in the Golden Years?

Rachel Nuwer | | READ MORE

Rachel Nuwer is a freelance science writer based in Brooklyn.