Solomon, the wisest man who ever lived, knew 3000 years ago, that joy had positive effect on health, funny, how it took until now, for our medical geniuses to "discover" it, eh?

Excerpted from

Using laughter-provoking movies to gauge the effect of emotions on cardiovascular health, researchers at the University of Maryland School of Medicine in Baltimore have shown for the first time that laughter is linked to healthy function of blood vessels. Laughter appears to cause the tissue that forms the inner lining of blood vessels, the endothelium, to dilate or expand in order to increase blood flow.

When the same group of study volunteers was shown a movie that produced mental stress, their blood vessel lining developed a potentially unhealthy response called vasoconstriction, reducing blood flow. That finding confirms previous studies, which suggested there was a link between mental stress and the narrowing of blood vessels.

The results of the study, conducted at the University of Maryland Medical Center, were presented at the Scientific Session of the American College of Cardiology on March 7, 2005, in Orlando, Florida.

The endothelium has a powerful effect on blood vessel tone and regulates blood flow, adjusts coagulation and blood thickening, and secretes chemicals and other substances in response to wounds, infections or irritation. It also plays an important role in the development of cardiovascular disease.

“The endothelium is the first line in the development of arteriosclerosis or hardening of the arteries, so, given the results of our study, it is conceivable that laughing may be important to maintain a healthy endothelium, and reduce the risk of cardiovascular disease,” says principal investigator Michael Miller, M.D., director of preventive cardiology at the University of Maryland Medical Center and associate professor of medicine at the University of Maryland School of Medicine. “At the very least, laughter offsets the impact of mental stress, which is harmful to the endothelium.”