Half the group was assigned to exercise for two 20-minute sessions or one 30- to 40-minute session four times a week. They walked, jogged, used a treadmill or stationary bike or went swimming. The other half chose a variety of social or cultural activities, such as cooking classes, art lectures, concerts and playing bingo.
At the end of the study, the improvement in sleep quality for the exercise group was startling: The participants now said their sleep quality was "good," ranking it below 5 on the 14-point sleep quality scale. They also said they felt much less depressed and said their daytime sleepiness had been significantly reduced.
The non-exercise group, however, may have learned more about art or cooking, but they were still tired and grumpy. They showed no improvement in sleep quality, daytime sleepiness or depression.
Phyllis Zee, M.D., director of Northwestern's Sleep Disorders Center and senior author of the study, says sleep is an essential part of health — as important as good nutrition. "By improving a person's sleep, you can improve their physical and mental health. If a person isn't sleeping well, we know they are more likely to be in poor health with problems managing their hypertension or diabetes."
So what is it about exercise that improves our sleep? "That is the million dollar question," says Zee. "Sleep and physical activity are intimately involved in regulating metabolism and mood." The study indicates that aerobic exercise "is a simple strategy to help people sleep better and feel more vigorous."
In addition to getting regular exercise, Zee has these tips for older adults who may be having trouble getting enough z's at night:
- Go to bed and wake up at the same time every day, even on weekends. It helps your body establish a sleep-wake cycle and will help you fall asleep more easily.
- Avoid caffeine at least six hours before sleep time so your body has time to eliminate its stimulant effects. (And not just coffee and tea, but soft drinks and energy drinks with caffeine as well. Yes, that means you with the Mountain Dew or Diet Coke. Did you know that stuff has more caffeine than tea?)
- Avoid alcohol before bedtime. (You may think it's a sedative, but it actually disrupts sleep.)
- Get out in the bright light during the day. Then at night, dim the lights and make sure your bedroom is cool, dark, quiet and comfortable.
Candy Sagon writes on health and nutrition for the Bulletin.
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