Some scientists believe that regular exercise may be the single best and safest method for improving sleep. Exercise has many wonderful effects on the body, all of which may contribute to better sleep. Exercise forces the body to work harder than usual, which means that we generally need more sleep to recuperate from the physical exertion. Exercise also increases the body's production of endorphins and other hormones that lead to feelings of calm and well–being. However, time of day matters. Working out at night may energize you, ultimately keeping you awake. If you're struggling with insomnia, limit vigorous exercise to the morning or afternoon. Calming routines like stretching or yoga poses are fine any time of day.