“There are sound, scientific reasons why we call robust, unrestrained laughter “hearty.” It produces complete, relaxed action of the diaphragm, it exercises the lungs, it increases the blood’s oxygen level, and it gently tones the entire cardiovascular system! In addition, the laughter response increases the production of endorphins-the body’s natural painkillers and pleasure opiates. We must learn to give laughter a high priority.”
-Bernie S. Siegel M.D., 1988.