Probably everyone knew that sleeping plays an important role in one's health life. Studies show that if you get 7-9 hours per night, you can expect to enjoy a healthier, usually happier life. It also helps tremendously with exercising. Adequate sleep gives you more energy and stamina. So next time you "just don't feel like exercising," consider how much sleep you got the night before. I guarantee that there is a direct relationship between the two.