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Yawning Explained: Why Are Yawns Contagious?

There are many mysteries in medicine, but the simple reflex of yawning is one that continues to fascinate people. Why do we all feel the involuntary urge to stretch our mouths open wide for a deep breath? And perhaps even more perplexing, why are yawns contagious?

For centuries, people thought yawning was related to sleep, boredom, or a need for oxygen. That’s logical, considering that the deep breath of a yawn brings in more oxygen than a typical breath. However, researchers have found that putting people in low-oxygen or high-carbon-dioxide environments did not make them yawn more, disproving that theory.

To date, there is still no scientific consensus on why we yawn. Newer studies suggest that there is more to yawning than having low energy levels. Our bodies may actually be trying to accomplish some more purposeful goals. Some popular theories about why we yawn include the following.

Some evidence suggests that yawning is your body’s attempt to keep you awake. Yawning is associated with a release of hormones that briefly increase your heart rate and alertness. You may yawn when waking up in the morning. Scientists theorize that yawning may be an evolutionary response that goes back to a time when being asleep or inattentive was dangerous.

In situations of rapidly changing elevations, such as riding an elevator or airplane, most people find themselves voluntarily or involuntarily yawning to relieve discomfort. When you yawn, tiny muscles in your ear contract and relax to open the Eustachian tubes and equalize pressure. This has led scientists to theorize that yawning serves as a defense reflex of the ear.

A more recent theory proposes that yawning has another physiological purpose: regulating brain temperature. Your body experiences a number of temperature transitions during the day due to sleep cycles, hormones, physical exertion, stress, your external environment, and more. Scientists think that if your brain is too warm, it triggers a yawn to flush warm blood away from the skull and bring in a cooler supply. Research shows that brain temperature does indeed fall after a yawn, and people are more likely to yawn in warmer environments than colder ones.

Although there is no scientific consensus on why we yawn, everyone does seem to agree that yawning is a collective experience. In fact, your likelihood of yawning increases after seeing someone else do it. Maybe you’ve even yawned while reading this information about yawning. It’s clear we’re highly suggestible to contagious yawning, but why?

The most common theory for explaining contagious yawning is that it’s a form of empathy or social mirroring. Research suggests that seeing or hearing another person yawn activates a whole network of brain regions associated with group social behavior. In the evolutionary history of contagious yawning, it may have been an unconscious form of nonverbal communication that helped our early ancestors bond and stay safe.

Interestingly, contagious yawning isn’t just a human trait. This primitive reflex originates in the primary motor cortex of other highly social mammals, including chimpanzees and dogs. In humans, the involuntary imitation of yawning begins around the age of four, which links it to the development of empathy in early childhood. 

Everyone yawns, but a jaw-gaping sigh in the middle of an important conversation or meeting can make you look unprofessional, bored, or uninterested, even when you’re not. If yawning seems to strike you at socially inopportune moments, try these tricks for stopping a yawn:

Take a few slow, deep breaths through your nose and exhale through your mouth. Research shows inhaling ambient air cools off blood vessels in the nose and sends cool blood to the brain. This results in a lower brain temperature, which has been shown to reduce yawning.

To subdue a mid-meeting yawn, try gritting your teeth. If you seal your lips and breathe through your nose, you might be able to avoid the embarrassment of a socially awkward yawn.

If you’re headed to a meeting, avoid eating hot foods. Instead, opt for cooling snacks such as watermelon or cucumber to stay hydrated and reduce body heat. Keep a glass of ice water within reach, and when you feel that yawn coming on, stifle it with a sip.

Research shows that the yawn reflex is related to regulating brain temperature, and you’re much more likely to yawn in warm environments. Cool things down by lowering the thermostat, wearing lighter layers of clothing, or applying a cool compress. In a recent study, people who placed a 40-degree-Fahrenheit cold pack on their neck yawned three times less frequently than those who wore a heating pad.

If your yawns are the result of a late night, try getting in some steps. A 2017 study found that a brief stint of low-to-moderate stair walking had the same energizing effects as a low dose of caffeine. 

The average healthy person yawns about 20 times per day. By and large, the yawn reflex is a normal and common automatic body response. Yawning is also a side effect of some antihistamines and some pain relievers, as well as medications used to treat depression or anxiety, such as serotonin reuptake inhibitors.

Less commonly, excessive yawning could signal an underlying health issue. When frequent yawning is caused by something more serious, it’s usually accompanied by other concerning symptoms such as persistent fatigue, dizziness, confusion, chest pain, or breathing difficulties.

Medical conditions associated with increased yawning include:

  • Sleep problems such as insomnia, apnea, and narcolepsy
  • Migraine headaches
  • Problems with the body’s temperature control
  • Bleeding in or around the heart
  • Heart attack
  • Stroke
  • Epilepsy
  • Multiple sclerosis
  • Parkinson’s disease
  • Liver failure
  • Brain tumor

Talk to your health care provider if you experience unexplained excessive yawning, especially if there’s a sudden increase in how much you’re yawning. They may conduct a physical exam and order tests such as electroencephalogram or magnetic resonance imaging to help pinpoint the cause and provide specific treatment.

From social connection to brain cooling, there’s a lot more to yawning than the need for a nap. Scientists are just beginning to uncover its social, psychological, and neurological significance. Finding out why yawning is contagious could even lead researchers to novel insights and treatments for a wide range of neural disorders such as epilepsy, dementia, autism, and Tourette syndrome.

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