Laughter really is medicine and it doesn't only improve mood. Studies show that laughter can also prevent disease, stimulate the immune system, lower resting blood pressure, relieve stress, reverse depression, and reduce the need for pain medication.
A recent study shed some light on exactly how laughter works. Oxford researchers found that laughing triggered the brain to release endorphins, which are natural "feel-good" chemicals with opiate-like effects.
Through a series of six experiments, study participants viewed sitcoms or comedy shows before they were subjected to discomfort, like wearing a tight blood pressure cuff and squatting for long periods of time. Researchers found that 15 minutes of laughter increased their pain threshold by 10 percent.
However, results were dose-dependent. Deep belly laughs that caused people to run out of breath or feel physically exhausted made the most difference.
The best part? Laughter had no negative side effects.
Bennett MP et al. The effect of mirthful laughter on stress and natural killer cell activity. Alternative Therapies in Health and Medicine. 2003 Mar-Apr;9(2):38-45.
Dunbar RI et al. Social laughter is correlated with an elevated pain threshold. Proceedings, Biological Sciences, The Royal Society. 2011 Sep 21.
Fonzi L et al. [Laughter and depression: hypothesis of pathogenic and therapeutic correlation]. [Article in Italian] Rivista di psichiatria. 2010 Jan-Feb;45(1):1-6.
Fry W and Savin WM. Mirthful laughter and blood pressure. Humor - International Journal of Humor Research. Volume 1, Issue 1, Pages 49–62, ISSN (Online) 1613-3722, ISSN (Print) 0933-1719, DOI: 10.1515/humr.1922.214.171.124, //1988
Mora-Ripoll R. The therapeutic value of laughter in medicine. Alternative Therapies in Health and Medicine. 2010 Nov-Dec;16(6):56-64.
Lefcourt HM et al. Humor and immune0system functioning. Humor - International Journal of Humor Research. Volume 3, Issue 3, Pages 305–322, ISSN (Online) 1613-3722, ISSN (Print) 0933-1719, DOI: 10.1515/humr.19126.96.36.1995, //1990
Rotton J and Shats M. Effects of State Humor, Expectancies, and Choice on Postsurgical Mood and Self-Medication: A Field Experiment. Journal of Applied Social Psychology, 26: 1775–1794. (1996) doi: 10.1111/j.1559-1816.1996.tb00097.x