Sleep and Exercise

Exercise has been proposed as offering a safe and healthy means of alleviating insomnia and other sleep disorders. This entry discusses the impact of sleep disorders, reviews the surveys and epidemiologic evidence supporting the benefits of exercise, and discusses the potential mechanisms by which exercise can promote healthy sleep patterns.

In industrialized countries, the annual global incidence of insomnia is approximately 30%. The prevalence of sleep problems increases with age, such that more than 50% of adults over age 60 have some sleep-related complaint.

Insomnia has been associated with physical and mental illness, impaired quality of life, and increased risk of automobile accidents. Moreover, in the United States, the costs associated with the resulting worker absenteeism, declines in work productivity, and increases in health care utilization have been estimated at approximately $14 billion.

Individuals’ reactions to disturbed sleep and self-help strategies can often exacerbate and perpetuate insomnia. For example, excessive worry about insomnia and attempts to compensate by spending extra time in bed can lead to a vicious cycle dynamic of further sleep problems.

Many physicians who are untrained in dealing with sleep problems are most inclined to treat patients with sleeping pills. However, sleeping pill use has been associated with daytime sedation, “sleep driving,” and impaired cognition; and chronic nightly use has been associated with a mortality risk comparable with that associated with smoking a pack of cigarettes per day.

Hence, there has been an increased interest in cognitive/behavioral treatments for insomnia. There is compelling scientific evidence that these treatments are superior to sleeping pills for chronic treatment of insomnia. However, the treatments are costly and time-consuming, and there are not enough clinicians who are trained to administer these treatments. Thus, other self-administered treatments would be helpful.

Exercise is almost invariably included in both expert and lay recommendations for improving sleep. The expectancy that exercise promotes sleep is centuries old; moreover, the notion that exercise promotes sleep has been consistent with historical [Page 1344]theories about the function of sleep. For example, theories that sleep serves an energy conservation or body restitution function naturally led to hypotheses that energy utilization and body tissue breakdown associated with exercise could elicit unique needs for sleep. These theories influenced much of the earlier research on exercise and sleep. However, they have been largely discredited on the basis of evidence, for example, supporting the idea that sleep is associated with only a minimal reduction in oxygen consumption and no particular increase in protein synthesis or replenishment of adenosine triphosphate (ATP) stores.

Undoubtedly, some of the interest in this topic stems from anticipation that exercise could be a very attractive alternative or adjuvant treatment for insomnia. Exercise has profound health benefits and would be a comparatively safe, inexpensive, and simple means of improving sleep. Besides affecting insomnia and sleep quality, there are also theoretical and empirical rationales for expecting that exercise could be a useful alternative or adjuvant treatment for several other sleep disorders, such as sleep apnea, restless legs syndrome, and circadian rhythm sleep disorders.