What are the short and long term benefits of exercise?

In general the body of research conducted over the last two decades indicates that the immediate effects of exercise include lessening negative mood states and magnifying positive mood. For example, a study designed to test how much exercise is needed before a person feels better found improvements in mood after only 10 minutes of moderate intensity aerobic exercise. Reductions in anxiety state generally occur after a bout of moderate to intense aerobic exercise with the immediate relaxation benefits typically extending for at least several hours. Longer term exercise protocols as well as direct measures of fitness also show more sustained benefits, such as overall reduced negative affect often coupled with enhanced well-being. The effects are not sustained, however, if an exercise program is discontinued.