There appears to be a large association between exercise and better sleep.
“Exercise is great for sleep. For the millions of people who want better sleep, exercise may help,” says David Cloud, CEO of the National Sleep Foundation.
The National Sleep Foundation’s 2013 'Sleep in America' poll says self-described exercisers report better sleep than self-described non-exercisers even though they say they sleep the same amount each night (6 hours and 51 minutes, average on weeknights). Vigorous, moderate and light*exercisers are significantly more likely to say “I had a good night’s sleep” every night or almost every night on work nights than non-exercisers (67%-56% vs. 39%). Also, more than three-fourths of exercisers (76%-83%) say their sleep quality was very good or fairly good in the past two weeks, compared to slightly more than one-half of non-exercisers (56%).
The report goes on to say that those who report exercising close to bedtime and earlier in the day do not demonstrate a difference in self-reported sleep quality. In fact, for most people exercise at any time seems to be better for sleep than no exercise at all.
“Exercise is beneficial to sleep. It's time to revise global recommendations for improving sleep and put exercise—any time—at the top of our list for healthy sleep habits,” says Dr. Barbara Phillips, poll task force member.