Laughter May Build Healthy Blood Vessels
A Good Laugh May Be Good for the Heart
March 7, 2005 -- "Rent two comedies and call me in the morning," may
sound like an unusual prescription, but a new study shows that laughter may be
good medicine for the heart.
Researchers found that watching a funny movie had a healthy effect on blood
vessel function, allowing them to expand and contract more effectively in
response to changes in blood flow.
But watching a mentally stressful movie, like a war drama, may have the
opposite effect, causing the lining of the blood vessels, known as the
endothelium, to narrow and restrict blood flow.
"The endothelium is the first line in the development of atherosclerosis
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 researcher Michael
Miller, MD, director of preventive cardiology at the University of Maryland
Medical Center, in a news release. "At the very least, laughter offsets the
impact of mental stress, which is harmful to the endothelium."
Miller presented the results of his study this week at the Scientific
Session of the American College of Cardiology in Orlando, Fla.
Laughter Fosters Healthy Blood Vessels
In the study, researchers had a group of 20 healthy men and women watch two
movies at opposite ends of the emotional spectrum and then measured the movies'
effects on their blood vessels via ultrasound.
On separate days the participants watched a 30-minute segment of Saving
Private Ryan, a war drama thought to cause mental stress, and
Kingpin, a comedy that would cause laughter. Blood vessel reactivity
was measured before and after watching the movies.
The results showed that each movie provoked strikingly different effects on
blood vessel function.
For example, blood flow was reduced in 14 of the 20 volunteers after
watching the movie clips that caused mental stress. But beneficial blood vessel
effects and relaxation were found in 19 of the 20 volunteers after watching the
On average, artery diameter increased by 22% during laughter and decreased
by 35% during mental stress.
"The magnitude of change we saw in the endothelium is similar to the
benefit we might see with aerobic activity, but without the aches, pains, and
muscle tension associated with exercise," says Miller. "We don't
recommend that you laugh and not exercise, but we do recommend that you try to
laugh on a regular basis. Thirty minutes of exercise three times a week, and 15
minutes of laughter on a daily basis is probably good for the vascular