Exercise Improves Sleep – But Takes Time

A good night's sleep will improve motivation to exercise.
Karin Heineman, ISTV Executive Producer

Doctors often recommend a morning jog or a trip to the gym to help patients with insomnia get a better night's sleep. But will an hour of exercise today really mean a restful sleep tonight?

"I was doling out this advice but the feedback I was getting back from my patients [was] that 'I tried it and I didn’t feel any better,'" said Kelly Glazer Baron, a psychologist at Northwestern University Feinburg School of Medicine in Chicago.

Baron decided to study the effects on exercise on sleep. Her study included eleven female participants ages 57 to 70 with insomnia. The researchers examined the participants' daily sleep and physical activity habits from a wristwatch monitor and exercise logs.

The results showed two interesting things: First, working up a sweat today will not help you sleep soundly tonight. It takes more time.

"It’s really been shown that exercise improves sleep over at least four maybe eight, and in our study, we found 16 weeks of exercise. We really didn’t see any improvement until 12 weeks," said Baron.

Second, "most people expect that sleep improves with exercise but we found actually that exercise improved after sleep," Baron said.

Researchers found that a good night’s sleep is the key to improving your exercise tomorrow, and people exercise less after a poor night's sleep.

"What sleep influences is motivation, how hard exercise feels and also perhaps your mood and whether or not you want to do it or not," said Baron.

In the study, patients felt more tired in the first four to eight weeks, but sticking to an exercise program helped lengthen sleep by 45 minutes – a big deal for someone with insomnia.

“If they have a poor night of sleep they shouldn’t give up on their exercise, and they should basically just go out and do it,” said Baron.

Get Inside The Science:

Exercise No Quick Cure for Insomnia

Kelly Glazer Baron, Northwestern University 

Author Bio & Story Archive

Karin Heineman is the executive producer of Inside Science TV.