It could be that you have experienced the exercise “high” that is a result of endorphin release. Endorphins are hormones that are secreted by the pituitary gland in the brain. Exercise, especially intense and prolonged exercise causes the increased release of these hormones. Endorphins cause blockages in pain reception, decrease in appetite and stress or anxiety as well as cause the euphoric sensation or “high”.
These symptoms are similar to those produced by morphine because endorphin and morphine are very closely related in chemical composition and effect. Exercise is often prescribed for depression and other mood disorders because of the psychologically uplifting benefits.
There are lots of reasons to exercise: for health, longevity and wellness. Having that endorphin rush and feeling great is an added bonus!