Regular exercise helps you fall asleep faster and into a more deep sleep. Sleep is brought on by chemicals released in your body which are a by-product of your body burning sugar for fuel during the day. The more sugar you burn through exercise and physical activity, the more of these chemicals are released, thus helping you sleep better and deeper. Your transition between the cycles and phases of sleep is also improved by exercise and they become smoother and more regular. When you are well-rested, your concentration, productivity and mood are greatly enhanced.