http://www.sciencedaily.com/releases/2011/08/110828101806.htmScienceDaily (Aug. 29, 2011) — Watching a
funny movie or sitcom that produces laughter has a positive effect on
vascular function and is opposite to that observed after watching a
movie that causes mental stress according to research conducted at the
University of Maryland School of Medicine in Baltimore, Maryland.
The idea to study positive emotions, such as laughter came about
after studies had shown that mental stress caused blood vessels to
constrict,” says Dr. Michael Miller, Professor of Medicine and lead
In their initial study more than 10 years ago, 300 men and women with
or without heart disease completed a questionnaire related to
situational-humor. For example, if you went to a party and saw someone
wearing the same clothes as you, on a scale of 1 to 5 (ranging from not
funny at all to very funny) how would you respond? The volunteers with
heart disease were 40% less likely to find these situations funny. Even
though this study was unable to prove whether a humorous response to
situations in daily life may protect against heart disease, (or the lack
of such a response is more common after a heart attack), it led to the
next series of studies testing whether laughter may directly affect
In this manner, volunteers watched segments of a funny movie, such as
“There’s something about Mary” on one day and on another day watched the
opening segment of the 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 with 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.
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 disease.
“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
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.
This research was presented at the European Society of Cardiology
Congress in Paris August 28, 2011
The above story is reprinted (with editorial
adaptations by ScienceDaily staff) from materials provided by
European Society of Cardiology (ESC).