Researchers at Loma Linda Univer­sity in Southern Cali­fornia have found a phys­i­o­log­ical change occurs when people laugh, lasting long after the laughter subsides. Laughter, according to the scien­tists, stim­u­lates the produc­tion of beta-endor­phins, also known as the body’s own morphine, and human growth hormone, which helps tune up the immune system.

Read the ABC News.com report on the study.