Of the handful of studies that have been performed, they suggest that exercise significantly improves the sleep of people with chronic insomnia. The only study that looked at the effects of a single exercise session found that a bout of moderate-intensity aerobic exercise (e.g., walking) reduced the time it took to fall asleep and increased the length of sleep of people with chronic insomnia compared to a night in which they did not exercise. However, in the same study, vigorous aerobic exercise (e.g., running) or lifting weights did not improve sleep. Similar results have been found for studies that examined the effects of long-term exercise on sleep in adults with insomnia. In these studies, after 4 to 24 weeks of exercise, adults with insomnia fell asleep more quickly, slept slightly longer, and had better sleep quality than before they began exercising.
