Repetitive, mirthful laughing is a physical act, one that involves contracting your muscles and deep breathing, similar to exercise. Research has shown, in fact, that hearty laughter leads to similar responses in your body as a moderate workout, such as decreases in stress hormones, benefits to cholesterol levels, enhanced immune activity and improved mood. Now, you won’t get extreme toned legs and buff arms, but you may be able to skip a workout once a week in exgange for some hearty laughter.