National Geographic News

Susan Brink

for National Geographic

Published June 6, 2014

We all want to believe that laughter is good for what ails us, but the science backing that up is thin. Most studies have been small and have relied on self-reported assessments.

Still, a rollicking good guffaw can't hurt. Or can it? There are rare instances of laughter prompting an asthma attack and even rarer instances of it triggering a stroke. And though this hasn't been part of a formal study, one researcher speculates that if you're surrounded by people laughing inappropriately—finding, say, a cockfight hilarious—it increases stress.

However, a few studies relying on laboratory testing do show some benefits.

"A good belly laugh leads to the release of endorphins from the brain," says Michael Miller, director of the Center for Preventive Cardiology at the University of Maryland Medical Center in Baltimore.

That release sets off a cascade of heart-healthy biological events. Endorphins, pleasure-inducing neurotransmitters, activate receptors on the surface of the endothelium, the layer of flat cells lining blood vessels. That leads to the release of nitric oxide, which widens blood vessels—increasing blood flow, lessening inflammation, inhibiting platelet clumping, and reducing the formation of cholesterol plaque.

A 2005 study by Miller measured the blood flow of 20 volunteers before and after watching a funny movie and a sad movie. After the sad movie, blood flow was more restricted in 14 of the 20 viewers. But after the movie that made them laugh, average blood flow increased by 22 percent.

"The best laugh is one that brings tears to our eyes," says Miller, author of Heal Your Heart: The Positive Emotions Prescription to Prevent and Reverse Heart Disease, scheduled for publication by Rodale Press in September. His prescription: at least 30 minutes of exercise at least three times a week—and 15 minutes of daily laughter.

You Have to Laugh Out Loud

Funding for laughter and humor research is low—so low that when Mary Bennett, director of the Western Kentucky University School of Nursing, wanted to look into the effect of laughter on the immune system, she found herself scrounging, asking other researchers for vials and other equipment from their labs. "It's really hard to get taken seriously when you say you study laughter," she says.

But her study of 33 healthy women, published in 2003, showed that those who laughed at a humorous movie had higher levels of natural killer cell activity, which increased their ability to fight off disease. However, the effect was seen only in the subjects who laughed out loud, not in those who quietly watched the comedy.

A study in Japan that also used laboratory findings found that laughter could improve anti-inflammatory factors in the blood of people who have rheumatoid arthritis.

But the bulk of the research on laughter and health depends on subjective studies and not on evidence-based science. And some studies are contradictory. One study of 70 depressed elderly women found that laughter yoga was just as effective as exercise therapy in improving mood, as measured by self-satisfaction reports by subjects. Humor and laughter may improve muscle tone, though only when someone is laughing, and some studies do show that a good laugh can help reduce stress hormones. But other studies show that laughter doesn't affect those hormones, according to a review of the literature published by Bennett.

No doubt, a New Yorker cartoon, a good joke, or an hour spent with the Marx Brothers can feel therapeutic. But when Bennett, who has spent much of her career studying laughter and poring over the research literature, is asked whether laughter cures or prevents any disease, her quick answer is a simple "No."

Still, she adds, "I think it's a useful adjunct of real medicine. If you're going through something like chemotherapy, anything you can do to help you stay sane through something that nasty will help."

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15 comments
Robert Cheatle
Robert Cheatle

Mmmm. Laughter makes life more enjoyable. Does it matter if it makes people live longer or not? Quality v Quantity is a better question to research?

Sebastien Gendry
Sebastien Gendry


We want to believe we're rational, but the sad truth is that how we feel about something dictates what we choose to believe about it, regardless of what the facts are. Until the late 19th Century, the prevailing attitude towards laughter was a negative one as if Proverb 17:22 was an error in the text: “A merry heart doeth good like a medicine: but a broken spirit drieth the bones.” Church dogma suggested laughter was detrimental to spiritual wellbeing, and many commonly considered it impolite and sinful. Our relationship with laughter has changed tremendously over the course of the 20th Century, but old doubts have proven very resilient and we still have mixed feelings about it, despite over 40 years of extensive research that suggest beyond the shadow of a doubt that laughter is a legitimate form of preventive (lifestyle) medicine, and a complementary option to other established therapeutic strategies. If over 450 published medical research, 1000s of psychological studies and countless documented (albeit individual) reports coming from 5 continents over the course of 20 years aren't enough for you, then you just choose to be blind to the obvious. Maybe laughter is a threat to the world of medicine because it is so simple, powerful, and, er, free. See the documentation at http://www.laughteronlineuniversity.com/research/

Pyrrho Nist
Pyrrho Nist

What if you get happiness out of being negative? Does that count

Tiellie Garcia
Tiellie Garcia

I definitely know it works, its not a solver to all problems but everytime a certain somebody gets on my nerves they do the silliest remark afterwards and even when i want to stay mad i can't i start snickering n can't stop ... ahhhh can't stay mad even it i wanted to.

Lumina Gauthier
Lumina Gauthier

You know, I often wondered about the 80-year-old guys that run the gov't. What keeps them going?  Must be they laugh all the way to the bank! 

Donna Whitaker
Donna Whitaker

I takes less muscles in your face to laugh than to be sad or mad. Laughter is a good feeling and keeps you younger physical and mentally. I am all for a laughter.

KENNETH LANE
KENNETH LANE

Tired of trying to enjoy dining out while being treated to the guffaws of drunken stooges--so, no laughter translates to personal space violation for me---or am I just sick of inconsiderate people?

LM Bowland
LM Bowland


Laughter has never cured anything, but it's an effective tonic. Healthy laughter, rather than derogatory mirth, lifts a person up and makes him/her feel better physically and psychologically. Anything that can take a down mood and give it a bit of a lift can't be bad. And, best of all, it's free.


Peter Rickards
Peter Rickards

Laughter is the best medicine? What a joke! That makes me laugh! Wait, hey, I feel better now! :-)  Count me as a believer!

Rachel Boschen
Rachel Boschen

This is a really great article and I wish someone would fund the research because I believe it is the best medicine.  I have laughed so hard that I have had an asthma-like attack...and it never hurt so good...lol....Just the other night...I was actually cracking up IN MY DREAMS so hard that I woke up laughing so hard and then couldn't stop for almost 30 minutes....but after I was able to settle down, I lapsed back into the best sleep ever.  

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