11 Scientific Benefits of Having a Laugh

iStock.com/Petar Chernaev
iStock.com/Petar Chernaev

They say that laughter is "the best medicine," and as it turns out, there is some scientific truth to this assertion. Humor-associated laughter has numerous health benefits, so here are 11 reasons you should laugh it up.

1. Laughter is a sign of good will toward others.

Group of friends laughing in a restaurant
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Laughter may be unique to humans. Why do we do it? According to a 2010 study in BMC Complementary and Alternative Medicine, laughter and smiling are generally intended as a message of good will. The authors extrapolate that there is a similar function in primates, who use facial expressions with bared teeth to suggest friendliness and sociability. They write, "Because some forms of smiling are voluntary and easily faked, laughter, which requires a more synergetic contraction of the wider musculature, is believed to have evolved in humans to express a secure, safe message to others."

2. Laughter may reduce your blood pressure.

Two girls laughing in a car
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High blood pressure (hypertension) is one of the most dangerous side effects of stress, as well as a huge risk factor for heart disease and stroke. However, it's hard to be stressed when you're laughing, so researchers have investigated whether laughter can bring blood pressure down. There are more than a few studies that show a reduction of blood pressure after laughter, such as a 2017 study in the Journal of Dental and Medical Research, where 40 patients undergoing hemodialysis listened to CDs of comic shows for 16 30-minute sessions over eight weeks, and saw a decrease in blood pressure.

In 2011 researchers presented results of a three-month-long study at the American Heart Association's Scientific Sessions. Researchers exposed 79 participants to either a music or laughter therapy. Laughter was stimulated through "playful eye contact" and breathing exercises. Immediately after sessions, the blood pressure readings from the laughers lowered by 7 mmHg—(millimeters of mercury, how the blood pressure readings on a sphygmomanometer are abbreviated). In comparison, music therapy only brought blood pressure down by 6 mmHg.

After three months, the blood pressure readings significantly decreased overall by 5 mmHg among the laughers. People in the comparison group showed no change in blood pressure readings.

3. This had led to a treatment known as laughter yoga.

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The success of laughter studies on blood pressure and other ills has led to a unique kind of treatment known as "laughter yoga."

Dr. Madan Kataria, founder of the Laughter Yoga School, told Medscape, "You don't need any jokes, any humor, or any comedy. You don't even need to be happy. What we do is laugh in a group and initiate laughter as a form of bodily exercise, but when we have eye contact with others, this laughter becomes real and contagious."

Kataria led a study of 200 male and female individuals who participated in laughter yoga sessions for 20 to 30 minutes. The researchers stimulated laughter in the participants for between 45 seconds and one minute, followed by deep breathing and stretching for the duration of the sessions.

Subjects who laughed saw a reduction in their systolic blood pressure of more than 6 mmHg, a significant change from baseline and also significant when compared with a non-laughing control group. Diastolic blood pressure was also significantly reduced. In addition, their levels of cortisol, a stress hormone, were also reduced.

As a result, laughter yoga has gone on to be used as an intervention for a variety of health issues, ranging from stress to dementia.

4. Laughter can reduce anxiety and other negative emotions.

Two guys laughing and shaking hands
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A 1990 study in Psychological Reports looked at the effects of humorous laughter on threat-induced anxiety. Researchers led 53 college students to believe (falsely) that they were going to receive an electric shock after a waiting period.

Subjects in the experiment group listened to a humorous tape while waiting for their shock. The placebo group listened to a non-humorous tape, and the control group did not listen to any tape. The humor group reported that their anxiety decreased during the anticipatory period, and those with the highest self-reported level of sense of humor had the lowest reported anxiety.

Laughter therapy has also been shown to improve anxiety in patients with Parkinson's disease [PDF], reduce anxiety and depression in nursing students, and improve optimism, self-esteem, and depression in menopausal women.

From a general psychological perspective, author Bernard Saper suggests in a paper for Psychiatric Quarterly that the ability to maintain a sense of humor and the ability to laugh can act as positive coping mechanisms to help a person get through difficult times.

5. Laughter is an immune booster.

Mom and boy laughing on couch
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At the beginning of cold and flu season, it may be a good idea to practice some laughter therapy, as several studies have shown the immune boosting power of a chuckle.

In one 2015 study on postpartum mothers in the Journal of Alternative and Complementary Medicine, researchers tested hand-expressed breast milk for immunoglobulin (IgA, antibodies that play an important role in immune function) before and after laughter therapy.

Twice a week, participants engaged in group "laughter dance routines" and some light breast massage while inducing laughter. Mothers who participated in the laughter therapy saw a small increase in their IgA. However, even a small amount was significant to the researchers, given that the postpartum period is when natural IgA in breast milk declines (it is at its highest level right after delivery, in the earliest, nutrient-dense breast milk known as colostrum).

Another study with college students found that watching funny movies increases salivary IgA (sIgA). Researchers have also found small examples of laughter's ability to increase the body's natural killer cells (NKs), a type of lymphocyte that is easy to test for in the blood. One study in the American Journal of Medical Science, albeit small—a cohort of only 10 male subjects—found significantly increased NK cell activity in the experimental group. Additional studies have shown increases in NK cell activity after laughter therapy or humorous videos, but most of these studies were done on male subjects.

6. Laughter may act as a natural anti-depressant.

woman laughing with dog
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While nobody would recommend laughter in lieu of other treatment for depression, it has shown promise at ameliorating depressed moods. Patients in long-term care facilities often suffer from depression and poor sleep, so a 2017 study in the Korean Journal of Adult Nursing [PDF] tested the effects of laughter therapy on 42 residents of two long-term care hospitals. The results were promising.

The laugher therapy, which the subjects undertook over eight sessions, for 40 minutes twice a week, included "singing funny songs, laughing for diversion, stretching, playing with hands and dance routines, laughing exercises, healthy clapping, and laughing aloud."

The results showed reduced depression and general mood improvement as well as improved sleep in the experiment group compared to the control group.

Another 2015 study in the Journal of Alternative and Complementary Medicine found that three 60-minute laughter therapy sessions improved the depression and negative mood states of cancer patients.

7. You breathe better after laughing.

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It turns out that a good bout of deep belly laughter can lead to increased heart rate, respiratory rate, and oxygen consumption, which are similar to what happens during exercise. While a 2009 study in the International Journal of Humor Research found that these changes only last as long as the laughter itself, if you can laugh like that for 30 minutes to an hour, maybe you can skip the gym.

8. Laughter is good for your cardiovascular system.

women laughing at a movie
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Your lungs aren't the only organ that benefits from a great guffaw. A 2009 study in Medical Hypotheses found powerful benefits to the heart and cardiovascular system.

Study participants watched either a comedy like Saturday Night Live or the bleak opening sequence of Saving Private Ryan, which is known to increase mental stress. They used a technique called brachial artery reactivity testing (BART), a form of ultrasound that looks at the brachial artery. Participants who watched the stressful movie experienced a 35 percent reduction in flow-mediated vasodilation (FMD, or how blood vessels dilate and contract); sluggish FMD is a risk factor for atherosclerosis. Meanwhile, the group that watched the funny scene saw a 22 percent increase in FMD, comparable to exercise. In short, laughing helped their blood flow better.

The American Heart Association recommends laughter for a healthy heart, adding that research has shown laughter promotes reduced artery inflammation and increased production of HDL, or "good" cholesterol.

9. Laughter calms stress hormones.

man and woman laughing
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Humor, and by extension, laughter, stimulates multiple physiological systems that decrease levels of stress hormones, such as cortisol and epinephrine, and increase the activation of the dopamine-dispensing reward system of the brain, according to researchers of a 2017 study in Advances in Physiology Education. A 2003 study in Alternative Therapies in Health and Medicine found that viewing a funny film decreased a wide variety of stress hormones.

10. Social laughter can relieve pain.

Girl with broken arm laughing in doctor office
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Laughter might be as good as some analgesics for pain, something early physicians seemed to understand. In the 14th century, French surgeon Henri de Mondeville used humor to distract patients from the pain of surgery and to help them during recovery.

More modern research has found that participants who watched comedy videos needed less pain medication than those who watched control videos. In a 2011 study published in the Proceedings of the Royal Society, over the course of six experiments using extreme cold as a pain-tolerance measure, researchers found that social laughter—laughter done in groups in a social context—elevates pain thresholds. The authors suggest, "These results can best be explained by the action of endorphins released by laughter."

11. Laughing burns calories.

Woman laughing on a running trail.
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As if all of these benefits aren't a good enough reason to giggle every day, a 2014 study in the International Journal of Obesity found that laughter can burn calories. Researchers broke a group of 45 participants into two groups, half of whom watched film clips intended to evoke laughter for approximately 10 minutes, and half who watched film clips unlikely to stimulate laughter. Both groups were attached to a "calorimeter" that measured energy expenditure and heart rate. They determined that those who laughed during their viewing burned up to 10 calories in 10 minutes, as compared to those who did not laugh and did not burn any calories.

Sssspectacular: Tree Snakes in Australia Can Actually Jump

sirichai_raksue/iStock via Getty Images
sirichai_raksue/iStock via Getty Images

Ophidiophobia, or fear of snakes, is common among humans. We avoid snakes in the wild, have nightmares about snakes at night, and recoil at snakes on television. We might even be born with the aversion. When researchers showed babies photos of snakes and spiders, their tiny pupils dilated, indicating an arousal response to these ancestral threats.

If you really want to scare a baby, show them footage of an Australian tree snake. Thanks to researchers at Virginia Tech, we now know these non-venomous snakes of the genus Dendrelaphis can become airborne, propelling themselves around treetops like sentient Silly String.

That’s Dendrelaphis pictus, which was caught zipping through the air in 2010. After looking at footage previously filmed by her advisor Jake Socha, Virginia Tech Ph.D. candidate Michelle Graham headed for Australia and built a kind of American Ninja Warrior course for snakes out of PVC piping and tree branches. Graham observed that the snakes tend to spot their landing target, then spring upward. The momentum gets them across gaps that would otherwise not be practical to cross.

Graham next plans to investigate why snakes feel compelled to jump. They might feel a need to escape, or continue moving, or do it because they can. Two scientific papers due in 2020 could provide answers.

Dendrelaphis isn’t the only kind of snake with propulsive capabilities. The Chrysopelea genus includes five species found in Southeast Asia and China, among other places, that can glide through the air.

[h/t National Geographic]

9 Facts About Narcolepsy

Korrawin/iStock via Getty Images
Korrawin/iStock via Getty Images

Everyone experiences occasional daytime sleepiness, but just a small fraction of the population knows what it’s like to have narcolepsy. The disorder is defined by persistent drowsiness throughout the day, and in some cases, sleep paralysis, hallucinations, and the sudden loss of muscle control known as cataplexy. Having narcolepsy can make doing everyday activities difficult or dangerous for patients, but unlike some chronic conditions, it’s also easy to diagnose and treat. Here are some facts you should know about the condition.

1. There are two types of narcolepsy.

If everything you know about narcolepsy comes from movies and TV, you may think of it as the disease that causes people to go limp without warning. Sudden loss of muscle control is called cataplexy, and it’s the defining symptom of type 1 narcolepsy. Type 2 narcolepsy, on the other hand, is mainly characterized by fatigue. Losing motor function while awake isn’t a problem for those with type 2.

2. Type 1 narcolepsy stems from a chemical deficiency.

Almost every patient with type 1 narcolepsy has low levels of hypocretin. Hypocretin is a neurochemical that regulates the wake-sleep cycle. When there isn’t enough of this chemical in the brain, people have trouble staying conscious and alert throughout the day. Most people with the second, less severe type of narcolepsy have normal hypocretin levels, with about a third of them producing low or undetectable amounts. Type 2 narcoplepsy has been studied far less than type 1 of the disorder, and scientists are still figuring out what causes it.

3. The exact causes of narcolepsy aren’t always clear.

So why do some people’s brains produce less hypocretin than others? That part has been hard for scientists to figure out. One possible explanation is that certain autoimmune disorders cause the body to attack the healthy brain cells that make this chemical. This disorder can be the result of genetic and environmental factors. Although people with narcolepsy rarely pass it down to their offspring (this happens less than 1 percent of the time), the sleep condition does occasionally crop up in family clusters, suggesting there is sometimes a genetic component at play. Head trauma that impacts the area of the brain responsible for governing sleep can also lead to narcolepsy in rare cases.

4. There are tests to diagnose narcolepsy.

If patients believe they might have narcolepsy, their doctors might ask them to detail their sleep history and keep a record of their sleep habits. There are also a few tests potential narcoleptics can take to determine if they have the condition. During a polysomnography test, patients spend the night at a medical facility with electrodes attached to their heads to monitor their breathing, eye movement, and brain activity. A multiple sleep latency test is similar, except it gauges how long it takes patients to fall asleep during the day.

5. Strong emotions can trigger cataplexy.

Cataplectic spells can sometimes be predicted by triggers. In some patients, feeling strong emotions—whether they’re crying, laughing, angry, or stressed—is all it takes for them to lose muscle control. These triggers vary from patient to patient, and they can even affect the same person randomly. Some people deal with them by avoiding certain situations and closing themselves off emotionally, which can disrupt their social lives.

6. Narcolepsy can make sleep terrifying.

Narcoleptics don’t just worry about their disorder during their waking hours. When they’re trying to fall asleep at night or wake up in the morning, narcolepsy can complicate things. One symptom is experiencing vivid, dream-like hallucinations while transitioning in or out of consciousness. These visions are often scary and may involve an intruder in the room with the sleeper. If they happen as the patient falls asleep, the hallucinations are called hypnagogic, and if they occur as they wake up, they’re hypnopompic.

A related symptom is sleep paralysis. This happens when a person’s brain cuts off muscle control of their body before they’re fully asleep or as they’re waking up. This combined with hypnagogic or hypnopompic nightmares can cause frightening experiences that are sometimes confused for real encounters.

7. Narcoleptics sometimes do activities half-asleep.

To outside observers, narcolepsy is sometimes hard to spot. A narcoleptic patient overcome by sleepiness won’t necessarily pass out in the middle of what they’re doing. Some act out “automatic behavior,” which means they continue with their actions—whether that’s walking, driving, or typing—with limited consciousness. This can cause poor performance at work or school, and in worst case scenarios, accidents while driving a car or operating machinery.

8. Harriet Tubman may have had narcolepsy.

One of the most famous likely narcoleptics in history is Harriet Tubman. The African American abolitionist was known to suffer from what were probably sudden narcoleptic episodes. The condition may have stemmed from the severe head trauma she sustained when a slave master threw an iron at another slave and hit her instead. The injury left her with permanent brain damage: In addition to narcolepsy, she also experienced chronic seizures and migraines throughout her life.

9. Medications and lifestyle changes are common narcolepsy treatments.

Though there’s no way to cure narcolepsy completely, there are many treatment options available. Taking medication is one of the most common ways to manage the disorder. Stimulants such as modafinil and armodafinil can be used to combat mild sleepiness, while amphetamines are often prescribed for more severe forms of fatigue. For hallucinations and sleep paralysis, selective serotonin reuptake inhibitors and serotonin and norepinephrine reuptake inhibitors—drugs that suppress REM sleep—can help.

As an alternative or supplementary treatment to medications, doctors may recommend lifestyle changes. Sticking to a sleep schedule, exercising regularly, avoiding nicotine and alcohol, and taking naps during the day can all reduce the symptoms of narcolepsy.

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