Sleep and exercise: is the benefit all mental?

The popular belief is getting regular physical exercise will make sleeping easier and more restful. A vocal group of sleep researchers are questioning the legitimacy of this conventional wisdom.

The New York Times recently published an article summarizing provocative recent research on the benefits of exercise.

A Swiss study suggests the benefit is all mental. People sleep better because they believe they’re improving their sleep through exercise.

The authors were unable to make any direct correlation between sleep and amount of physical exercise. College students in the study who rated themselves low on a perceived fitness scale tended to report problems sleeping. Those who rated high on the same scale reported sound sleep. The correlation between how much they exercised and how perceived fitness was not very high.

A past study had difficulties linking regular exercise with quality of sleep. Researchers were unable to find any pattern in sleep and exercise habits based on diaries completed by U.S. college students. The same study also reported active adults fell asleep only a minute and a half faster than their inactive peers. The data was taken from monitors that recorded their movements and sleeping patterns.

Further research suggests increasing exercise may increase slow wave sleep, however this effect was did not hold true for marathon runners and frequent exercisers. Body temperature may play a part in the relationship between exercise and deep sleep.

While it is debatable on how exercise impacts normal sleep, there are preventative benefits. Physical fitness reduces the risk for the development of obstructive sleep apnea, a sleep disorder often tied to obesity.

Weight loss through dieting and regular exercise is part of a treatment strategy recommended by the AASM for people who are obese and have sleep apnea. Research suggests weight loss provides relief by reducing the severity of sleep apnea. This treatment should be combined with CPAP or an oral appliance to improve the quality of sleep and reduce the risk of serious complications.