Describes benefits of laughter (e.g., relaxes muscles, stimulates production of “feel-good” brain chemicals, increases blood flow to the peripheries). Anger and hostility can reverse these positive changes. (Carter, Rita, Ed. Exploring Consciousness. p 199. CA: University of California Press, 1998.)

A good sustained belly laugh results in a rise in endorphin production and a decrease in adrenaline and cortisol. (O’Brien, Mary, MD. Successful Aging. p 152-153. CA:Biomed General. 2007.)

Studies: laughter releases endorphins and boosts serotonin levels, triggering a feeling of well-being that encourages emotional and physical healing. Fifteen seconds of hearty laughter equals about three minutes on the rowing machine. (University of Texas MD Anderson Cancer Center. Laughter Really is Good Medicine.)

Laughter has been shown to increase endorphin levels, stimulate immune function, reduce cortisol, stimulate circulation, massage internal organs, and have positive effects on the cardiovascular and respiratory systems. (Lubbe, Francois. UK Editor for The Healthier Life. Laughter has Potential Medical Benefits.

Laughter triggers the release of endorphins, as well as increasing natural killer cells that can fight diseases from colds to cancer. (Beck, Martha, PhD. The Joy Diet. p 154-156. NY: Crown Publishers, 2003.)

Laughter stimulates the pituitary gland that triggers the release of endorphins, some of which can remain in the body for 12 hours, producing an ongoing natural high. (Greenwood-Robinson, Maggie, PhD. 20/20 Thinking. p 104. NY: Avery, Putnam Special Markets, 2003.)

Both crying and laughing trigger the release of endorphins (e.g., natural internal chemicals similar to heroin and morphine) into the bloodstream. (Pease, Barbara and Allan. Why Men Don’t Have a Clue and Women Always Need More Shoes. p 60-62. NY: Broadway Books, 2004.)

Laughter reduces pain by releasing endorphins that are more potent than equivalent amounts of morphine. (Gallozzi, Chuck. Benefits of Laughter. )