Laughing lowers levels of stress hormones and strengthens the immune system. Six-year-olds laugh an average of 300 times a day. Adults only laugh 15 to 100 times a day.

Blood sugar levels. One study of 19 people with diabetes looked at the effects of laughter on blood sugar levels. After eating, the group attended a tedious lecture. On the next day, the group ate the same meal and then watched a comedy. After the comedy, the group had lower blood sugar levels than they did after the lecture.

Relaxation and sleep. Cousins, who was diagnosed with ankylosing spondylitis, a painful spine condition, found that a diet of comedies, like Marx Brothers films and episodes of Candid Camera, helped him feel better. He said that ten minutes of laughter allowed him two hours of pain-free sleep.

Immune response. Increased stress is associated with decreased immune system response, says Provine. Some studies have shown that the ability to use humor may raise the level of infection-fighting antibodies in the body and boost the levels of immune cells, as well.

Laughter increases energy levels. Feeling tired or run down? Have a good laugh. Laughter is a natural pick-me-up, which may provide the energy and time needed to do things that might otherwise be avoided.

Laughter is good exercise. Laughing 100 times has the same effect on the body as being on a rowing machine for 10 minutes or a stationary bike for 15 minutes.

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