A good workout doesn’t guarantee a better night of sleep.
The idea that people need sleep to recover from the wear and tear of exercise is over-rated, a researcher says.
“The evidence shows exercise just does not have that much effect on sleep,” said researcher Shawn Youngsted of the University of California, San Diego.
Youngsted reviewed 38 studies and pooled data from 401 research subjects to cover just about all phases of sleep, from nodding off to waking up.
The review, published in the journal Sleep of the American Sleep Disorders Association and Sleep Research Society, was an attempt to see if popular preconceptions about the benefits of sleep matched the facts.
“Most people think that, if they had a physically active day, they would sleep better,” Youngsted said.
But the research indicates that an active day doesn’t make much difference, he said.
In all, exercisers had about 10 minutes more sleep than non-exercisers, the study found. And people who exercised more also slept longer, it found.
Because the average sleep period was about 7 hours, the difference doesn’t mean exercisers need - or benefit from - appreciably more sleep, Youngsted said. But it doesn’t rule out a greater need for sleep after very long, hard exercise, he said.
And the studies examined only normal sleepers, so it’s not known if poor sleepers would improve their sleep a lot after exercise.
The studies also looked at what happened after a single exercise session, not for any cumulative effects built up in a habit of exercise.
“The most interesting group was not able to be done,” said researcher Ofreu Buxton of the University of Chicago. “The chronic exercise group could show the greatest benefits.”