How laughter affects every part of your body.
Kevin Lee Smith bounds to the front of the room, grabs a microphone and utters a few words. Then something comes over him: A cascade of chemical messengers in his brain throws Smith into convulsions.
For several seconds, he loses voluntary control over most of his body. His legs, arms, back and chest tense. His facial muscles squeeze upward. His stomach muscles and diaphragm spasm. His heart races. His blood pressure spikes. Someone call 911; give the man a sedative!
But Smith's audience is also experiencing the same phenomena: They are, of course, laughing.
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ComstockComplete.comValue of a Giggle
Laughter is so common a human experience, we forget how bizarre it is. When aliens first see us laugh, they'll think we're having some sort of fit (and they probably won't get the punch line either). Smith causes the hilarity by talking about his growing forehead: "My hairline is making a beeline for my behind." Those chemicals cascade, bodies convulse, laughter erupts.
Smith informs the audience that he's a male nurse: "Some people think it's unusual for a man to be a nurse. But there are male nurses throughout the country. Every once in a while the seven of us get together to talk about things." He teaches a course on humor and medicine at the University of Minnesota and came to this medical conference at Loma Linda University in California to argue that laughter has medical benefits. That notion is at least as old as Proverbs 17, "A merry heart doeth good like a medicine" (which wasn't saying much back then, unless you liked leeches). It's also an idea that some mind-body fanatics, with more enthusiasm than medical proof, have oversold. But in the past few years, a brave group of scientists, fewer in number than male nurses, has been trying to uncover the physiology of laughter and its provable medical benefits. Foremost among these researchers is Loma Linda professor Lee Berk, PhD, who organized the conference Smith addressed and who also stands convulsing in the room.
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"The jury is still out," says Robert Provine, a University of Maryland professor and author of Laughter: A Scientific Investigation, "and more work needs to be done." But the initial results are very encouraging. All the suggestions are that laughter is indeed good for you. So get those convulsions going and chuckle yourself to health.
Tickle laughter is a good place to start because it is, in fact, the most primal form of laughter. Or perhaps we should say the most primate form of laughter. Chimpanzees and other primates "play-fight," especially when young, and let out a rhythmic "pant-pant" that is the simian version of ticklish laughter, according to Provine, who has been studying the subject for decades.
Provine and others are convinced that laughter is deeply wired in our evolution, predating language. And its origin in tickling and play-fighting is more complicated than simple humor: We're being touched in our most sensitive (and lethal) areas, under the ribs, under the arms, under the neck. Maybe we laugh because we're pleased as punch that we're not actually getting beaten or killed. If so, we can chalk that up as laughter's first medical benefit!
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So just what is this ancient phenomenon of laughter? It's a preset program that involves the entire body. If it's a joke we hear, the phenomenon starts in the auditory nerves in our ears. If it's a comic strip, the program is triggered by our eyes. When a father tickles his son, nerve endings in the boy's skin send electric impulses to the spinal cord and up, triggering a reaction in the part of our brains responsible for sensing what's going on in our muscles, joints and on our skin. Similarly, someone hearing a joke or reading a comic strip sends that information to the brain for processing.
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A Natural High
Whatever the cause of a laugh, what happens next is not fully known. Scientists are actually starting to put people into functional MRI machines and make them laugh in order to find out. In a recent study at Stanford, researchers showed Bizarro comics to people while their brains were monitored by an MRI. They were able to prove for the first time that laughter (or at least humor) stimulates the parts of our brain that use the "feel good" chemical messenger dopamine. That puts laughter in the category of activities you want to do over and over again, such as eating chocolate or having sex. Dopamine systems that get out of whack can lead to addiction, says Emory University neurologist Gregory Berns. This finding explains why kids want to keep playing silly games until parents can't stand it anymore. Laughter is pleasurable, perhaps even "addictive," to the brain.
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Meanwhile, elsewhere in the brain of someone about to laugh, the supplementary motor area executes a bunch of commands, sending signals to dozens of muscles and glands all at once. The whole business of a laugh is what scientists call "stereotyped." People may make different noises and faces, laugh at different intensities, and have a different sense of humor, but the commands human brains give out during a guffaw are a recipe followed precisely. Here's what happens throughout the body:
Face Time: When we laugh, as many as 15 small muscles squeeze our faces into a smile. Increased blood flow there may turn us a bit pinker and give us a happy glow.
Eyes Have It: If the laugh is vigorous enough, our tear ducts can activate. Sometimes our glee can have a cumulative effect till we're literally crying with joy-and studies show that tears, whether happy or sad, may reduce symptoms of stress.
Mouth Off: Of course, our mouths open to let out those "ha-ha" rhythmic blasts of vocalized air. In addition, Loma Linda's Lee Berk and others have tested the saliva of patients after laughing episodes and found that they have higher levels of disease-fighting agents called immunoglobulins. Other studies have found higher blood levels of killer T-cells, suggesting that laughter may raise our immune function.
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Vocal Point: Our vocal equipment has to roll up its sleeves to produce our high-pitched hysteria. The diaphragm, a strong muscle under the lungs, pumps down and up, filling the lungs and then blasting air out of them, up through the voice box to produce the laugh. A hearty guffaw is quite a workout for this system, requiring as much effort and volume as yelling. Because the lungs are exchanging much more air than normal, they enrich the blood with oxygen.
Wrestle Your Vessels: Our heart rate and blood pressure spike briefly when we laugh (especially when laughing while wrestling). They increase a bit even when we chuckle while sitting in a chair watching a funny movie. In addition to possible immune benefits noted earlier, laughter seems to help diabetics keep their glucose levels in check.
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In a recent study, University of Maryland cardiologist Michael Miller investigated the effect of laughter on the inner lining of the blood vessels, or endothelium. Yep, even that part of our body produces chemicals-good ones when it expands, bad ones when it constricts. Miller put a pressure cuff on his subjects and blew it up to restrict blood flow for a few minutes. In the meantime, the victims (I mean subjects) watched a scene from a stressful movie (Saving Private Ryan) one day, and then a scene from a funny movie (There's Something About Mary or Kingpin) another day. Then Miller released the cuff and used an ultrasound machine to see whether the blood vessel lining expanded or contracted. By significant margins, it expanded after the funny movie and narrowed after Ryan. When the blood vessel lining expands, we get a shot of good chemicals like nitric oxide (not to be confused with nitrous oxide, or laughing gas), which reduces clotting and inflammation. When the endothelium contracts, we get a shot of stress hormones like cortisol, which make our blood clot and can lead, over time, to heart disease. View our picks for the top 100+ funniest movies of all time.
Pain Reliever: Whether in our extremities or up in our brains, laughter seems to have an analgesic effect: It increases our tolerance for pain. Back in 1987, Texas Tech psychologist Rosemary Cogan used the discomfort of a pressure cuff to test another medical benefit of laughter: pain management. Subjects who had watched a 20-minute Lily Tomlin routine could tolerate a tighter cuff than those who had watched an informational tape or no tape at all.
Belly Laughs: A hearty laugh can cause us to double over and tense all our major muscle groups for minutes at a time, leading Lee Berk to a simple conclusion: Laughter is exercise. He is fond of saying, "Laughter is inner jogging." The heart rate and blood pressure go up while you're laughing, but then they fall down below your baseline afterward, the same as with exercise. This could be very important exercise, Berk avers, for elderly and sick people who can't get out and run two miles.
According to Provine, early laughter researcher William Fry found that it took ten minutes on his rowing machine to elevate his heart rate to the same level provided by a good belly laugh, a finding that may have millions of Americans rationalizing their way out of the gym and back to reruns of Friends or I Love Lucy.
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Laughs Yourself Skinny
Can a few minutes of hearty laughter replace your treadmill time? No, but getting the giggles does burn some calories, and the more you laugh, the more you burn, say experts at Vanderbilt University.
Their study recruited 45 pairs of friends (we're more likely to laugh with others in the room than when we're alone) to watch comedy video clips, including episodes of Saturday Night Live and the movies There's Something About Mary and Austin Powers.
The volunteers viewed the scenes in a room equipped with a device that measures the number of calories burned, and each person was hooked up to a heart rate monitor. At the end of the session, researchers determined that laughing increased heart rate by 10 to 20 percent and burned about 1.3 calories per minute. That's similar to the so-called workout you'd get typing, filing, or playing cards. Jogging, on the other hand, burns about 10 calories per minute. "Pay attention to small things. Every calorie counts," says lead study author Maciej S. Buchowski, PhD. Chuckle for 15 minutes every day for a year and you could drop up to four pounds -- and that's nothing to laugh at.
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