A daily dose of laughter may be good for the heart because, like exercise, it makes blood vessels work more efficiently, researchers reported Monday.
Depression, on the other hand, can raise the risk of dying from heart failure, a separate study found.
The two studies, presented at a meeting of the American College of Cardiology in Orlando, Fla., show how psychological factors can affect a person’s health.
“We don’t recommend that you laugh and not exercise, but we do recommend that you try to laugh on a regular basis,” said Dr. Michael Miller of the University of Maryland School of Medicine in Baltimore. “Thirty minutes of exercise three times a week, and 15 minutes of laughter on a daily basis is probably good for the vascular system.”
Miller and colleagues at the school showed two movies, one humorous, one stressful, to 20 healthy volunteers and tested the function of their blood vessels.
The researchers specifically looked at the endothelium, the lining of the vessels, and found that blood flow was reduced in 14 of the 20 volunteers after viewing stress-inducing movie clips. But blood flowed more freely in 19 of the 20 when they laughed at funny movie segments.
Average blood flow increased 22% during laughter, and decreased 35% during mental stress, they said at the meeting.
In a second study, Dr Wei Jiang and colleagues at Duke University in North Carolina followed 1,005 heart failure patients and also tested them for depression.
Those with mild depression had a 44% greater risk of dying, Jiang said at the meeting.
“This adverse association of depression and increased long-term mortality was independent of other factors, including age, marriage, cardiac function and the root cause of the heart failure,” Jiang said.