The Reason Exercise Won’t Help You Sleep Better Tonight

People who exercise consistently also generally enjoy better sleep. But the relationship between working out and sleeping in is not a one-night stand. So if you haven’t exercised recently don’t expect one workout to instantly improve your slumber.

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

Baron’s long-term study showed that it can take four months of daily exercise to dispel insomnia and help you sleep more soundly. The study also showed people usually cut back on exercise following nights they don’t sleep well.

“Sleeping poorly doesn’t change your aerobic capacity, but it changes people’s perception of their exertion,” Baron said. “They feel more exhausted.”

The researchers believe that the brain functions that lead to poor sleep can be alleviated with exercise but the improvements can’t be accomplished right away.

“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,” says researcher Phyllis Zee. “Rather than medications, which can induce sleep quickly, exercise may be a healthier way to improve sleep because it could address the underlying problem.”