Laughter is good for the heart because it prolongs life while depression
increases the risk of an early death, according to two new studies.
A good bout of laughter every day provides similar cardiovascular benefits as
exercise because it stimulates the blood flow, said Michael Miller, who headed
one research team at the University of Maryland.
On the other hand, depression - or the lack of laughter - is often linked to
unhealthy habits such as smoking and drug addiction and increases the risk of
death by 44 per cent, said Wein Jiang, who led a study of 1,000 heart patients
for the University of North Carolina.
Miller said laughter produced a "magnitude of change ... in the endothelium
... similar to the benefit we might see with aerobic activity, but without the
aches, pains and muscle tension associated with exercise."
While laughter should not replace exercise, he said, "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 system."
Miller told the American College of Cardiology annual conference that he
showed excerpts of funny and stressful films to 20 non-smoking, healthy
volunteers, equally divided between men and women, whose average age was 33.
Researchers measured changes in blood vessel reactivity as the volunteers
watched the movies and noted striking contrasts.
Artery flow in the arms was reduced in 14 of the 20 volunteers following the
movie clips that caused mental stress. In contrast, beneficial blood vessel
relaxation increased in 19 of the 20 volunteers after they watched the movie
segments that generated laughter.
Overall, average blood flow increased 22 per cent during laughter, and
decreased 35 per cent during mental stress.
"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," Miller said.
However, the researcher was unable to explain the physiology of laughter's
benefits.
"Does it come from the movement of the diaphragm muscles as you chuckle or
guffaw, or does it come from a chemical release triggered by laughter, such as
endorphins ?"
"Perhaps mental stress leads to a breakdown in nitric oxide or inhibits a
stimulus to produce nitric oxide that results in vasoconstriction," he added.
On presenting the results of his research, Jiang said the "adverse
association of depression and increased long-term mortality was independent on
other factors, including age, marriage, cardiac function, the root cause of
heart failure."
"Approximately half of all patients with heart failure will die within five
years of diagnosis, and we believe that our study appears to identify a group of
these patients who are at a higher risk (44 per cent) of dying," she added.
Jiang was also unable to explain the results of her research theorizing
instead that "depressed patients tend to make unhealthy lifestyle choices in
such areas as diet and smoking."
Both studies, however, appear to show that emotional states can lead to real
physiological changes.
In February, researchers from the United States released details of a study
which indicated emotional shocks such as the end of a relationship or a surprise
party can kill otherwise healthy people. They called it a "broken heart
syndrome."
