Exercise improves sleep, but not overnight

It can take four months of regular aerobic exercise to help insomnia sufferers get a good night’s sleep, researchers say.

 

“If you have insomnia you won’t exercise yourself into sleep right away,” says lead study author Kelly Glazer Baron, a clinical psychologist and director of the behavioral sleep program at Northwestern University Feinberg School of Medicine. “It’s a long-term relationship. You have to keep at it and not get discouraged.”

 

This is the first long-term study to show aerobic exercise during the day does not result in improved sleep that same night when people have existing sleep problems. Most studies on the daily effects of exercise and sleep have been done with healthy sleepers.

The study also showed people exercise less following nights with worse sleep. “Sleeping poorly doesn’t change your aerobic capacity, but it changes people’s perception of their exertion,” Baron says. “They feel more exhausted.”

“This new study shows exercise and sleep affect each other in both directions: regular long-term exercise is good for sleep but poor sleep can also lead to less exercise. So in the end, sleep still trumps everything as far as health is concerned,” says senior author Phyllis Zee, a neurology professor at Feinberg and director of the Sleep Disorders Center at Northwestern Memorial Hospital.

Wait for it

Baron decided to analyze the daily effect of exercise after hearing her patients with insomnia complain the exercise she recommended didn’t help them right away. The findings are detailed in a study published in the Journal of Clinical Sleep Medicine.

“They’d say, ‘I exercised so hard yesterday and didn’t sleep at all,’” Baron says. “The prevailing thought is that exercise improves sleep, but I thought it probably wasn’t that simple for people with insomnia.”

“Patients with insomnia have a heightened level of brain activity and it takes time to re-establish a more normal level that can facilitate sleep,” Zee says. “Rather than medications, which can induce sleep quickly, exercise may be a healthier way to improve sleep because it could address the underlying problem.”

The study participants were older women, who have the highest prevalence of insomnia. Exercise is an optimum approach to promote sleep in an older population because drugs can cause memory impairment and falls. Baron thinks the results also could apply to men because there is no evidence of gender differences in behavioral treatments for insomnia.

For the study, Baron performed an analysis of data gathered by the team during a 2010 clinical trial that demonstrated the ability of aerobic exercise to improve sleep, mood, and vitality over a 16-week period in middle-age-to-older adults with insomnia. She and colleagues examined the daily sleep data from 11 women ages 57 to 70.

The key message is that people with sleep disturbances have to be persistent with exercise. “People have to realize that even if they don’t want to exercise, that’s the time they need to dig in their heels and get themselves out there,” Baron says. “Write a note on your mirror that says ‘Just Do It!’ It will help in the long run.”