For the nearly half of Americans who experience occasional insomnia, and the 22 percent who suffer from the condition nightly, a new survey by the non-profit National Sleep Foundation suggests the key to restful sleep is vigorous exercise. The survey of 1,000 people, conducted by phone and over the internet, indicates that people who exercise regularly have less problems getting to sleep and enjoy a better quality of sleep than those who do not. More than 75 percent of the respondents who reported themselves as working out regularly reported sleeping well, as compared to just over half of the people who reported not exercising at all. Interestingly, both groups reported getting the same amount of sleep; an average of just under seven hours a night during the work week. However, respondents who were physically active reported falling asleep more quickly, experiencing less sleeping problems and needing less sleep to function during the day. The sedentary people reported problems falling asleep at night, staying asleep, keeping awake during the day, taking more naps and exhibiting more symptoms of sleep apnea, a condition that causes breathing problems while sleeping. The experts concluded that even ten minutes of exercise a day could have a significant impact on the duration and quality of sleep.