A good chuckle doesn’t just cheer us up. Doctors are discovering that it can ease pain and even help fight disease. Go on, have a giggle, says Roger Dobson
Laughing at Charlie Chaplin can be a serious business. Chortling at a funny film may seem to be an activity with few consequences for health, but research shows that it does more than exercise the 20 or so face muscles involved in laughing. When researchers showed a group of mothers with babies diagnosed with eczema, Chaplin’s Hard Times or a weather documentary, those who laughed at the funny film had higher levels of melatonin in their breast milk. And when their babies were fed the melatonin-rich milk, they had fewer allergic reactions.
“Our results show that laughter of mothers may be helpful in the treatment of infants with eczema,” say the doctors at the Moriguchi-Keijinkai Hospital in Japan, who carried out the study.
The study is among the latest research to show that laughter, humour and happiness play a key role in good health and longevity, and can positively affect diseases and conditions as diverse as high blood pressure, flu, heart disease, arthritis and diabetes. As NHS nurses start attending laughter workshops to encourage them to lighten up and make hospital stays a more pleasant experience for patients, research is increasingly showing the value of laughter and humour.
The concept that laughter is good for you is also being used in therapy to improve quality of life, provide some pain relief, encourage relaxation, and reduce stress. Some centres now provide some kind of humour therapy – one in five National Cancer Institute treatment centres in the US offer it – and it can involve watching films, listening to tapes, reading books or attending humour workshops. It can also be combined with exercises, such as yoga.
But can it do more than ease stress and act as a distraction? Can laughter actually affects the progression of illness, boost the immune system, and reduce symptoms of diseases such as rheumatoid arthritis?
It has long been accepted that low mood, including depression, can have a negative effect on physical health. Patients who are depressed at the time of heart bypass surgery, for example, are more than twice as likely to die during the following five years. Stress chemicals triggered by being made redundant or getting divorced can also double the likelihood of death from heart disease or stroke.
Now research is showing that laughter and humour can have a positive effect on health and longevity. Just how is not clear, but studies are throwing up some clues. Happiness and laughter have been shown to increase natural killer cell activity in blood and free radical-scavenging capacity in saliva, as well as lowering levels of the stress hormone cortisol. It is also thought that laughter causes the release of special neurotransmitter substances in the brain, endorphins, that help control pain. And there are more direct physical effects of laughter, including increased breathing, more oxygen use, and higher heart rate.
Some research suggests that laughter can boost the immune system. When researchers at Japan’s Osaka University Graduate School of Medicine showed a 75-minute funny film to a group of men and women, they found that that blood levels of natural killer cells activity increased by 26.5 per cent.
Happiness also boosts the immune system. A study at Birmingham University found a link between higher levels of antibodies to flu and being in a happy marriage. Those with the highest marital satisfaction had the higher antibody responses to a flu vaccine after four weeks. A second study the University of North Carolina shows happiness in a marriage was linked to lower blood pressure, and fewer stress hormones.
A study from the Foundation for Advancement of International Science, also in Japan, showed that laughter seems to lower levels of a protein involved in the progression of diabetic nephropathy, a kidney disease that occurs as a result of diabetes and which is the leading cause of kidney failure. Levels dropped substantially and immediately after watching a comedy show. “The beneficial effects of laughter on preventing the exacerbation of diabetic nephropathy are strongly suggested,” say the researchers.
But one of the most important findings on the effects of laughter is its impact on inflammation, which plays a key role in a wide range of diseases, from arthritis to cancer, and which is a component of many age-related chronic diseases that often cause disability. Research reported in the Oxford University Press medical journal, Rheumatology, showed that blood levels of key inflammatory compounds dropped considerably after patients with rheumatoid arthritis watched a humorous film.
The researchers recorded amounts of what they call “mirthful laughter” and found that levels of interleukin 6, a cytokine that plays a central role in inflammation, dropped significantly in the arthritis patients, but not in a healthy comparison group. The anti-inflammatory effects have also been shown to last for 12 or more hours after the laughter has subsided.
Pain can be eased by laughter too. When researchers at the University of California exposed children aged between seven and 16 to a pain experiment, where they put their hands into very cold water, those who watched a funny video and laughed were able to tolerate more pain.
While the mechanisms involved in the effects of laughter on immune and other body systems are poorly understood, some effects have more straightforward explanations. Laughter is thought to trigger changes in breathing patterns that may have a therapeutic effect for patients with chronic lung disease. In some of the latest research at University Hospital Basel in Switzerland, doctors have been testing the idea that laughter can reduce hyperinflation in patients with chronic obstructive pulmonary disease, which has been estimated to effect up to 900,000 people in the UK. Results show that humour therapy reduced hyperinflation in patients who have severe COPD.
Dieters, too, may be unlikely beneficiaries of the direct physical effects of laughter. Researchers at Meharry Medical College, Nashville, have gone to some lengths to calculate the energy expended in a laugh. With the help of four funny film clips, a calorimeter, a heart rate monitor, and digitised audio data for counting the number of laughs, they worked out that the energy loss from laughter was the equivalent of from 0.79-1.30 kJ/min (0.19-0.31 kcal/min). “Genuine voiced laughter causes a 10 to 20 per cent increase in energy use and heart rate,” they say.
That means, it’s suggested, that 15 minutes of jollity a day – or half an episode of Only fools and Horses – could be enough to laugh away the effects of a small chocolate bar.
Happiness is contagious, research finds
A study of the relationships of nearly 5,000 people tracked for decades in the Framingham Heart Study shows that good cheer spreads through social networks of nearby family, friends and neighbors.
They say misery loves company, but the same may be even more true of happiness.
In a study published online today in the British Medical Journal, scientists from Harvard University and UC San Diego showed that happiness spreads readily through social networks of family members, friends and neighbors.
Knowing someone who is happy makes you 15.3% more likely to be happy yourself, the study found. A happy friend of a friend increases your odds of happiness by 9.8%, and even your neighbor’s sister’s friend can give you a 5.6% boost.
“Your emotional state depends not just on actions and choices that you make, but also on actions and choices of other people, many of which you don’t even know,” said Dr. Nicholas A. Christakis, a physician and medical sociologist at Harvard who co-wrote the study.
The research is part of a growing trend to measure well-being as a crucial component of public health. Scientists have documented that people who describe themselves as happy are likely to live longer, even if they have a chronic illness.
The new study “has serious implications for our understanding of the determinants of health and for the design of policies and interventions,” wrote psychologist Andrew Steptoe of University College London and epidemiologist Ana Diez Roux of University of Michigan in an accompanying editorial.
Christakis and UCSD political scientist James H. Fowler examined the relationships of nearly 5,000 people who were tracked for decades as part of the landmark Framingham Heart Study.
They discovered that happy people in close geographic proximity were most effective in spreading their good cheer. They also found the happiest people were at the center of large social networks.
In many regards, they concluded, happiness is like a contagious disease.
“We know people who are most susceptible to HIV are people who have lots of partners,” Fowler said. “This is the same thing.”
This isn’t the first evidence that emotions can spread like a virus. Studies have found that waiters who offer service with a smile are rewarded with bigger tips. On the flip side, having a mildly depressed roommate made college freshmen increasingly depressed themselves.
Fowler and Christakis thought they could document the spread of happiness more convincingly by studying the copious records of participants in the Framingham study, a massive effort launched by the National Heart, Lung and Blood Institute in 1948 to find common causes of cardiovascular disease. Participants gave researchers the names of their parents, spouses, siblings, children and close friends, including many who were also study volunteers. That allowed the researchers to track multiple relationships for each participant out to several degrees of separation.
Fowler and Christakis focused on 4,739 people who were part of the second-generation cohort that joined the study in 1971, in part because many of them had parents and children in other cohorts. The researchers rounded out their networks by using home addresses to locate neighbors and employment information to identify co-workers. Altogether, they constructed a social network that included 12,067 study volunteers who were linked to each other through 53,228 ties.
In earlier studies of the network, Fowler and Christakis showed that obesity and smoking spread among groups of friends and relatives.
To assess happiness, the researchers relied on how much the volunteers said they agreed with four statements like “I was happy” and “I enjoyed life.” The questions were asked three times between 1983 and 2003.
The results were striking:
A happy friend who lives within a half-mile makes you 42% more likely to be happy yourself. If that same friend lives two miles away, his impact drops to 22%. Happy friends who are more distant have no discernible impact, according to the study.
Similarly, happy siblings make you 14% more likely to be happy yourself, but only if they live within one mile. Happy spouses provide an 8% boost – if they live under the same roof. Next-door neighbors who are happy make you 34% more likely to be happy too, but no other neighbors have an effect, even if they live on the same block.
“We suspect emotions spread through frequency of contact,” Fowler said. As a result, he said, people who live too far away to be seen on a regular basis don’t have much effect.
The one exception was co-workers, perhaps because something in the work environment prevented their happiness from spreading, the study found. The research was funded by the National Institute on Aging and the Robert Wood Johnson Foundation.
Shigehiro Oishi, a University of Virginia psychologist who studies the causes and consequences well-being, said the importance of geography was a profound finding.
“Although we are connected with friends and family members who live far away via cellphone and the Internet, these results indicate that there is nothing like a face-to-face interaction,” Oishi said. “We are told to get connected by cellphone companies, but in order to get connected you really have to live close by and interact face to face.”
Fowler and Christakis said they didn’t know the mechanism by which happiness spreads. One possibility is that happy people spread their good fortune directly by being generous with their time and money. Evolution may have encouraged infectious happiness if it helped hominids and early humans enhance their social bonds so they could form successful groups, the researchers said.
UC Irvine sociologist Katherine Faust, who studies social networks, said the study might overstate the role of social ties in transmitting happiness. Many of the Framingham volunteers are the parents, siblings and children of other volunteers, and their propensity toward happiness could be grounded in their genes, she said.
But Richard Suzman, director of behavioral and social research at the National Institute on Aging, said Fowler’s and Christakis’ work was persuasive enough to force policymakers to rethink the importance of social ties when contemplating happiness or obesity or smoking.
“You can’t just treat individuals; you have to treat networks or communities,” he said.