Scientists claim that a sense of humor has both short-term and long-term positive effects on our bodies and minds. For example, in a short-term perspective, a sense of humor can stimulate your internal organs (due to fresh oxygen-rich air which you inhale when you laugh), such as the heart, lungs, and muscles, and free you from some physical effects of stress; when you laugh, your blood circulates faster, and different groups of muscles relax, which results in a better mood. Long-term effects include the strengthening of your immune system, improving your overall mood and satisfaction with life and yourself, and even pain relieve; laughter is known to be able to break the pain-spasm cycle common to some muscle disorders (MayoClinic).