Yawning: Why we yawn and why is it contagious

According to studies, the average adult yawns about 20 times per day.

According to studies, the average adult yawns about 20 times per day. Photo: Getty

Theories about yawning and why is it contagious have circulated for years.

Many people believe it brings oxygen into the body.

Dr Mark Schier, a senior physiology lecturer at Swinburne University, told The New Daily that yawning “reboots and resets our respiratory system”.

The average yawn can last six seconds and is contagious from person to person.

The average yawn can last six seconds. Photo: Getty

Why do we yawn?

A 2014 study published in Physiology & Behaviour showed the underlying reason for yawning in humans “appears to be involved with brain thermoregulation”, in other words brain temperature.

The study tested 120 people across distinct temperatures and seasons. The outcome was that “yawning was significantly lower during winter than summer”.

Furthermore, National Geographic reported it exists to cool down the brain.

“Yawning causes the walls of the maxillary sinus to expand and contract like a bellows, pumping air onto the brain, which lowers its temperature,” National Geographic reported.

Is yawning contagious?

Yes, it is contagious. It is triggered involuntarily when we observe another person yawn.

A 2017 study published in the Current Biology journal found that yawning is a “common form of echophenomena” which is “the automatic imitation of another’s words or actions”.

The study observed 36 adults in separate blocks who watched video clips of people yawning. They were instructed to either resist the yawn or allow themselves to yawn.

The participants’ brain activity were measured using transcranial magnetic stimulation (TMS) during the experiment.

The study found participants were only partially successful in resisting a yawn. The number of “stifled yawns” increased but there were few fuller yawns.

Georgina Jackson, Professor of Cognitive Neuropsychology in the Institute of Mental Health, said in a statement that “this research has shown that the ‘urge’ [to yawn] is increased by trying to stop yourself”.

Why do your eyes tear up when you yawn?

Swinburne University’s Dr Schier said that it was a “reflex pathway”. 

The eyes tear up because when we yawn “we are stretching the structures in the mouth and nose”.

“We are putting pressure on the nasolacrinal duct which is the duct that connects the side of our eyes to the back of our nose,” Dr Schier said.

According to Dr Schier, another reason why is because we may be opening our eyes quite wide when we yawn. This means there is “potential of dust to settle there” causing them to tear up.

Is yawning good for you?

Yes, it is good for you. Yawning is a way for the human body to reboot the oxygen supply.

Dr Schier said that it can get “rid of some of the extra carbon dioxide supply that may have built up in our blood stream and lungs”.

Yawning also provides some alertness. It opens the eyes, mouth and jaw and pulls back the ears which opens the ear canal a little wider.

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