Women are plagued more by sleep problems, especially women who are overweight and who don't take hormones after menopause begins, writes lead researcher Shelley S. Tworoger, PhD, with The Fred Hutchinson Cancer Research Center in Seattle. Her study appears in the current issue of Sleep.
Several studies have looked at the effect of exercise on sleep problems, finding that exercise indeed helps older people fall asleep and stay asleep. But does morning or evening work best? How much exercise should we get?
Walking early in the day -- for an hour each time -- worked wonders in relieving insomnia, according to this new study. "But something as simple as stretchingcan make a difference," Tworoger tells WebMD.
The Exercise-Sleep Connection
The 173 women involved in Tworoger's study were between 50 and 75 years old -- none were taking menopausal hormone therapy. They were all overweight and got less than an hour of moderate-to-vigorous exercise in a week's time. All had sleep problems -- trouble falling asleep without medication, and trouble staying asleep.
The women were randomly assigned to either an aerobic exercise regimen or stretching. Classes were held at 10:30 a.m. and 6 p.m. Some days, the women did their workout at home instead.
In the aerobic classes, intensity was gradually increased over the first three months. The women did a 45-minute workout five days a week -- mostly walking or biking.
The stretching group attended 60-minute low-intensity stretching and relaxation sessions several days a week, or did their workout at home. Morning and evening classes were an option for this group, too.
One year later, the results came in:
- Morning exercisers who worked out at least 3.5 to 4 hours a week had less trouble falling asleep.
- Exercising less than three hours a week did not help sleep problems as much.
- The evening exercisers had more trouble falling asleep than the morning exercisers. Those who got more exercise at night got the least improvement. Those who got less evening exercise had more benefit.
Stretching also helped relieve sleep problems, but to a lesser degree. The stretching group needed less sleep medication and had less trouble falling asleep than before the study.
"Something as simple as stretching can make a difference," says Tworoger. Also, whether they did their stretching in the morning or evening didn't make any difference -- they got some relief from sleep problems, she adds.
What's Going On?
"Possibly, exercise affects hormones and circadian rhythms -- the body clock," Tworoger says. "Exercise in the morning could affect those hormones differently than exercise at night. Also, body temperature starts to go down before sleep, and exercise can increase body temperature."
When it comes to relieving sleep problems, "any exercise is better than no exercise," says Richard Rosenberg, PhD, director of science and research at the American Academy of Sleep Medicine. He agreed to comment for WebMD. "Certainly, exercise and improved fitness level are part of good sleep hygiene."
"The idea that exercise might be influencing circadian rhythms is interesting," Rosenberg adds. "We know that regular exercise can affect circadian rhythm. The effects can be as strong as light exposure. These findings are provocative."
But whether you exercise (or stretch) in the morning or evening shouldn't make a difference, he says. "If you give yourself two or three hours for your body to cool down after exercise, you shouldn't have sleep problems."
A cool shower can help your body cool down. But a warm bath two hours before bedtime has been shown to also help offset any sleep problems, he says.