Will We Ever Solve the Mystery Surrounding Why We Yawn?

Caroline de Braganza


(Image by Victoria Borodinova from Pixabay)

Did you know the name of the field of scientific study related to yawning is called chasmology?

French doctor Olivier Walusinski, who organized research and discussion into the topic, officially coined the name by using the Greek term for "opening wide", khasma.

We yawn for a variety of reasons.

  • We’re bored, tired, or nervous.
  • We yawn before sleep and on waking.
  • We yawn when under stress or under stimulated.

Yawning is an age-old process that occurs not only in humans but reptiles, birds and mammals.

Contagious yawning is common in humans and other animals such as dogs and chimpanzees. Scientists don’t yet fully understand this phenomenon.

Yawning is a brain cooling mechanism

Research reveals that yawning cools the brain.

So, if you’re feeling hot and bothered—yawn!

“This behavior is controlled by chemicals in the brain called neurotransmitters. Neurotransmitters, such as nitric oxide and dopamine, act in the *hypothalamus to induce and control yawning.” -Brain HQ

* (The hypothalamus is a control mechanism in your brain which regulates temperature and breathing, among a host of other functions such as blood pressure, pulse, digestion, and sweating. It also controls your sleep cycles and connects to the pituitary gland which plays a role in producing dopamine.)

The above description doesn’t include everything the hypothalamus does, but shows how complex our brains are. No wonder it baffles scientists!

When we yawn, hyperthermic (hot) blood is flushed away from the skull and replaced with a flow of cooler arterial blood.

A study published in Physiology & Behaviour in 2019 supports this theory.

“Manipulating neck temperature alters contagious yawning in humans”

The researchers indirectly manipulated people’s brain temperature by having them hold a lukewarm, warm or cold compress firmly against their neck over their *carotid arteries for five minutes.

* (These are the major blood vessels in the neck that pump blood towards the brain.)

The 92 participants then watched a 63-second video depicting a random series of nine individuals yawning. They then completed a questionnaire to assess their yawning behavior and advise the number of hours they slept the previous night.

Those who had cooled their brains had less of an urge to yawn than those of the warm and room temperature groups. Only 48.5 percent of the cool group felt like yawning, while the warm group scored 84.8 percent and the room temperature group 69.2 percent.

"These findings are consistent with earlier research showing that yawns function as a compensatory brain cooling mechanism," said study author Andrew C. Gallup, an assistant professor of psychology at SUNY Polytechnic Institute.


(Image by Lorri Lang from Pixabay)

We yawn less in winter

Gallup also conducted studies, where he surveyed people during winter and summer months in a warm city (Tucson, AZ) and a cooler one (Vienna, Austria). In both studies, the season had a significant effect on how often people yawned.

"People are less likely to yawn when the surrounding air temperatures exceeds body temperature because taking a deep inhalation of air warmer than your own body would not result in cooling," he said.

This also helps explain why we often yawn when waking up or falling asleep. These are times when our bodies go through their major changes in temperature and might need a little help keeping it in check. When we're getting ready for bed, we see a significant drop in body temperature, perhaps aided by an enormous yawn or two. And when we're waking up, our bodies are warming rapidly.

Are yawns contagious?

Psychologists have proven that the more empathetic you are, the more likely you are to yawn when someone else does.

HuffPost Science reported, “Researchers discovered that the closer you are to someone genetically or emotionally, the more likely it is that you’ll ‘catch’ their yawn.”

Yawns are also contagious between humans and their dogs, chimps, baboons and budgerigars!

A few final yawns

A study in 2012 using high resolution ultrasound footage reveals that unborn babies yawn repeatedly in the womb. Scientists link this activity to brain development.

The average yawn last six seconds. During that time, your heart rate increases significantly, supporting the theory that the arterial blood flow to the brain increases—cooling it!

Excessive yawning is usually a sign of extreme boredom or fatigue. It’s not unusual during this pandemic, which has severely restricted our social activities outside the home.

Make sure you're engaging in activities that keep you stimulated and you are getting enough sleep.

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Published essayist. Follow me for local news that impacts our lives, plus stories on public and mental health. Through writing, I also share my passion for music, politics, our environment and social justice, and hope you find value in my words.


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