Preliminary results of a study reported at the recent AHA meeting show that laughter and a good sense of humor may have a positive effect on heart disease and artery disease. Researchers compared the humor responses to a questionnaire from 150 patients who had either had a heart attack or had a revascularization procedure such as angioplasty to those of 150 healthy controls. They found that the heart patients were 40% less likely to laugh in a variety of common situations.

According to the lead investigator, Dr. Michael Miller of the University of Maryland Medical Center in Baltimore, doctors may soon tell their heart patients to incorporate laughter into their daily activities, just as they now recommend other cardioprotective activities such as exercise. He cited examples such as reading something humorous or watching a funny video.

Compared to the control group, people with heart disease were less likely to recognize humor or use it as an adaptive mechanism, and they generally showed less ability to laugh, even in positive situations. “We don't know why laughing protects the heart, but we do know that mental stress is associated with impairment of the endothelium, the protective barrier lining our blood vessels,” Dr. Miller said. “This can cause a series of inflammatory reactions that lead to fat and cholesterol buildup in the coronary arteries - and ultimately to a heart attack.” Theoretically, he added, if laughter releases protective chemicals in the body, laughing when angry may counteract the potential adverse effects on the endothelium.