10. It enhances emotional well-being. Most people report that they feel calm and have a sense of well-being after they exercise. Exercise, according to one theory, releases beta-endorphin, a natural substance in the body that is hundreds of times more potent than morphine. Another theory points to serotonin as the cause of the exercise high. Increased levels of serotonin in the central nervous system are associated with feelings of well-being, heightening of appetite, and lessening of mental depression. The weight loss that accompanies exercise can also cause people to feel better about themselves.
Whether we’re fully conscious of it or not, we’re always looking for how to be happy. And exercise is one of the most obvious steps to take, as it’s not a coincidence that you feel better after a good workout: It’s science. A Penn State University study found that people who exercised, whether it was a mild, moderate or vigorous workout, had more pleasant feelings than those who didn’t. (1)