Laughter is good for the heart
2 October 2011
Having a good laugh has a positive effect on blood flow, while
stress constricts blood vessels and restricts blood flow.
A study by the the University of Maryland School of Medicine in
Baltimore, Maryland found that watching a funny movie or sitcom that
produces laughter has a positive effect on vascular function and
watching a stressful movie has a negative effect. The study was
presented at the European Society of Cardiology Congress 2011 in
Paris at the end of August.
"The idea to study positive emotions, such as laughter came about
after studies had shown that mental stress caused blood vessels to
constrict", said Dr Michael Miller, Professor of Medicine and lead
Volunteers watched segments of a funny movie on one day and on
another day watched part of a stressful movie (Saving Private Ryan).
Each volunteer served as his or her own control.
When study volunteers watched the stressful movie, their blood
vessel lining developed a potentially unhealthy response called
vasoconstriction, reducing blood flow. This finding confirms
previous studies, which suggested there was a link between mental
stress and the narrowing of blood vessels. However, after watching
the funny movie, the blood vessel lining expanded.
Overall, more than 300 measurements were made on 20 non-smoking
healthy men and women using ultrasound to measure blood vessel
diameter. The results showed that blood flow was enhanced by 22% in
those watching the funny film, but decreased by 35% in those
watching the stressful film — giving a 30-50% difference in blood
vessel diameter between the laughter (blood vessel expansion) and
mental stress (blood vessel constriction) phases. “The magnitude of
change we saw in the endothelium after laughing was consistent and
similar to the benefit we might see with aerobic exercise or statin
use” says Dr Miller.
“We’re not talking about a simple chuckle," he said, "but real
mirthful laughter," which, he added, should last for at least 15
seconds. Laughter, he explained, might exert its beneficial effect
through the release of endorphins by the brain, which activate
receptors on the endothelium which in turn lead to the release of
nitric oxide. “Nitric oxide dilates blood vessels, reduces
inflammation, cholesterol deposition and clotting,” said Miller.
The endothelium has a powerful effect on blood vessel tone and
regulates blood flow, adjusts coagulation and blood thickening, and
produces chemicals in response to injury and inflammation. It also
plays an important role in the development of cardiovascular
“The endothelium is the first line in the development of
atherosclerosis or hardening of the arteries, so it is very possible
that laughing on a regular basis may be useful to incorporate as
part of an overall healthy lifestyle to prevent heart disease. In
other words, eat your veggies, exercise and get a good belly laugh
every day" says Dr. Miller.
Although the results of the brachial artery blood flow
measurements appear to make a connection between laughter and
vascular health, more studies are needed. "What we really need is a
randomized clinical trial to determine whether positive emotions
reduce cardiovascular events above and beyond today's standard of
care therapies", concluded Dr Miller.