Here's something to smile about—an easy, no-cost prescription from the doctor. In addition to daily exercise, plenty of rest, and eating veggies, your doctor may recommend injecting a healthy dose of humor—20 to 30 minutes a day of laughter—into your diet, as well.

Laughter is a well-known anecdote for stress, pain, and conflict. Gelotology is the physiological study of laughter. We do know that laughter increases blood pressure, heart rate, changes in breathing, and causes a reduction in levels of certain neurochemicals. In addition to being fun, it relaxes you and connects you to others. But some laugh researchers believe it may have real benefits for the heart and immune system too.

If there's any doubt that laughter gives your body a workout that's easier than say, jogging, consider the last time you laughed so hard your belly hurt. Or think back to when you had an uncontrollable case of the giggles and laughed so hard you had to stop in order to catch your breath.

Michael Miller, MD, is a professor of medicine, epidemiology, and preventive medicine at the University of Maryland Medical Center who has been studying laughter and its effects on the body for much of his career. He believes there is a connection between laughter and cardiovascular health and one of his studies seems to support this theory.

In 2005, 20 male and female volunteers watched a humorous movie and a more serious one. There was a 95 percent increase in the blood flow of volunteers who watched a funny flick compared to 74 percent decrease in blood flow during the viewing of a more somber show. Dr. Miller who is also the director of the Center for Preventive Cardiology at UMMC said the benefits lasted 12 to 24 hours.

"Our research on laughter was the first to show a direct effect on heart health by expanding the inner lining of our blood vessels (endothelium), thereby serving as the gateway to vascular health," explained the researcher. "We do believe that laughter offers a measure of protection to the heart, but we lack data from a randomized controlled study to delineate this effect."

Dr. Miller and his colleagues also believe that the well-known effect of laughter's release of endorphins also leads to activation of the chemical nitric oxide that produces other beneficial effects. "In other words, endorphins not only make us feel good but lead to activation of other chemicals that support heart health," said the doctor.

Researcher William B. Strean, PhD, at the University of Alberta concurs with Dr. Miller and reports in an article for The Canadian Family Physician that the benefits of laughter have been shown in geriatrics, oncology, psychiatry, rehabilitation, rheumatology, home and hospice care and general patient care.

However, in his comprehensive review of laughter research he says the effect of laughter on the so-called stress hormones: epinephrine, norepinephrine, and cortisol is an area where questions remain. "If it turns out laughter does decrease stress hormones, it might explain the proposed connection between laughter and immune function and the resulting improved health outcomes," Strean said in the article.

Unfortunately there are no large laughter-based studies that have been published to date. A few smaller studies do seem to connect laughter to boosting the immune system. For example, one study of 52 male medical students in 2000 found a connection between watching humorous videos and the rise of T-cell activity in the blood. T-cells jump-start the body's immune system by attacking viruses. And another study found that laughter decreased disease-related symptoms, such as heart arrhythmias.

Writing about his personal experiences in Anatomy of an Illness (1979), author Norman Cousins described how he used laughter to cope with a painful and life-threatening joint and connective tissue disease. According to Cousins, "a 10-minute belly laugh resulted in two hours of painless sleep," significant since there were few treatment options at the time of his disease ankylosing spondylitis.

Outside of the realm of health care, the military has also been known to deploy laughter to help soldiers as well as their families back home cope with the stress of life in the trenches. When you laugh your mind stops thinking—it helps you relax and maintain a good mental balance.

According to Strean there are almost no negative side effects or undesirable ramifications associated with laughter as an intervention so it can't hurt to put more laughter in your life. Watch a silly program, go to a comedy club, read the comics, and surround yourself with funny people. Laughter is contagious. And as Dr. Miller says, "The bottom line is: laugh daily and quite possible you won't have to call me in the morning!"




American Heart Association

Email Interview With Michael Miller, MD
Professor of Medicine, Epidemiology and Public Health Director
Center for Preventive Cardiology
University of Maryland

American College of Cardiology