Laughter can stimulate many organs. Laughter improves the intake of oxygen-rich air, stimulates your heart, lungs and muscles and increases the endorphins that are released by your brain. Laughter can also stimulate circulation and aid muscle relaxation, both of which help to reduce some of the physical symptoms of stress. Laughter may ease pain by causing the body to produce its own natural painkillers. Laughter may also break the pain-spasm cycle common to some muscle disorders and Increase personal satisfaction.