Medical: Research shows laughter pays off for our health

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Maybe you still can't get away with paying for the next comedy you rent or see in a theater out of your health savings account.
But indications that a good giggle or two are good for you, psychologically and physically, continue to pile up credits in medical studies and literature.
Researchers love a good comedy -- or at least some clips from one -- to test the effects of guffaws. Often, they pair them with a documentary on some depressing topic to see if an emotional downer has an opposite effect.
There are physical changes when we laugh. Muscles stretch throughout the face, neck and body, pulse and blood pressure rise, and respiration increases, putting more oxygen in the bloodstream. It's like a little mini-workout, except that you're only likely to bust a gut, not a tendon.
As a straight calorie burner, laughter's not all that efficient. Scientists have calculated that 15 minutes of mirth might consume 50 calories -- about half what an average person might burn on a sedate one-mile walk.
There's more to the equation than just energy expenditure, however. For instance, scientists in recent years have found that subjects who were only told they were about to watch a funny film had a surge of hormones that elevate mood and boost immunity, and a drop in three hormones related to negative effects from stress.
Two studies presented by researchers from the University of Texas-Austin last week during the annual meeting of the American College of Sports Medicine, further demonstrated that laughter not only reduces stress, but also improves blood flow.
In one report, Jun Sugawara described a test run on 17 healthy adults, aged 23-42, who watched either an half hour comedy or a half hour documentary in separate sessions a day apart.
Before and after each viewing, the blood flow through the carotid arteries -- the main arteries that bring blood to the brain and face -- was measured. Blood flow -- or arterial compliance -- improved while watching the comedy, and remained at a higher level for 24 hours. There was no change in blood flow from watching the documentary.
A second study, led by Takashi Tarumi, was run much the same way, except that the outcome researchers measured was vascular function and blood vessel dilation. When another group of 10 volunteers watched a comedy or a documentary on Nazi death camps, there was more dilation -- relaxing -- of blood vessels from the comedy.
"Not only did comedies improve vascular dilation, but watching a documentary about a depressing subject was actually harmful to the blood vessels," Tarumi said. "Documentaries constricted blood vessels by about 18 percent."
Both reduced arterial compliance and constricted blood vessels contribute to high blood pressure.
But the volunteers in those studies were all apparently healthy adults. Lee Berk, a preventive care specialist at Loma Linda University in California and a pioneering researcher on the effects of humor and healthful hormones, reported results on a direct clinical dose of laughter added to the care of a group of diabetic patients.
Berk and Dr. Stanley Tan, a diabetes specialist at Oak Crest Health Research Institute in Loma Linda, divided a group of 20 high-risk diabetic patients who also had high blood pressure and high cholesterol, into two study groups.
All got their standard medications for their diabetes, hypertension and high cholesterol, but one group of 10 was also assigned to laugh for at least a half hour a day by watching a TV comedy or funny movie -- material they selected themselves.
Within two months, laughter group had lower levels of some stress hormones and inflammation factors, as well as rising levels of good (high density) cholesterol.
At the end of a year, the laughter group's good cholesterol levels had risen by 26 percent, compared to 3 percent for the control group, while levels of artery-damaging C-reactive proteins had declined 66 percent in Group L, compared to 26 percent in the control group.
Berk and Tan, who presented their results before the American Physiological Society's annual meeting in New Orleans in April, said the study suggests that adding laughter to standard pharmaceutical care for diabetes may lower patients risk for heart disease.
Or, as Sugawara said, "Laughing is likely not the complete solution to a healthy heart, but it appears to contribute to positive effects."
On the Net: http://www.acsm.org
Contact Lee Bowman at bowmanl(at)shns.com

The Medical Journal