Why do we yawn?

The human body, when in good health, can be considered as a perfect machine, often characterized by physiological mechanisms and reflexes that we sometimes take for granted. As with the act of yawning, for example.

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Yawning is a reflex present in mammals that consists of a long, open-mouthed inhalation followed by an equally long exhalation.

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This phenomenon occurs on several occasions, for example when we are very tired. It often happens that, just before going to sleep, the act of yawning has a better chance of occurring.

But it doesn't just happen when you're tired. Yawning can also occur after a meal or in specific situations or contexts, perhaps if they are boring.

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Some of you will also have experienced in your life that yawning can also be an extremely contagious act.

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But why do we yawn? In reality, there aren't any certain theories about the possible causes. In this gallery we look at the possible causes indicated by the website of the Sleep Foundation, a foundation in which a team of expert specialists in health and sleep works.

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Assuming that there is no verified theory as to why we yawn, the Sleep Foundation medical experts put forward some hypotheses.

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According to the first hypothesis suggested by the Sleep Foundation, yawning could be an attempt to wake up the brain during a moment of tiredness or boredom.

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In fact, the act of yawning forces the muscles of the face to move. Some scholars believe that during yawning there is an increase in heart rate due to having stimulated the carotid artery. Additionally, wakeful hormones are released.

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That the goal of the yawn is to awaken the brain is also traced back to another reason: skin conductance (SC), that is, the measurement of continuous variations in the electrical characteristics of the skin.

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According to scientists, electrical conductance increases during yawning, as does caffeine. This is why it is speculated that bringing the brain to a waking state is the main goal of a yawn.

To make this hypothesis very plausible there are some classic situations, in which the yawn occurs just when you need to pay more attention, such as while driving or in other passive situations.

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Another hypothesis put forward by the Sleep Foundation's experts is that yawning is of great help in 'cooling the brain'.

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This means that the movements of the face and neck during yawning can have a thermoregulatory function of the brain, thanks to which heat is easily dissipated.

Another reason that could support this hypothesis is the fact that some people's eyes water when yawning, with a possible consequent release of heat.

In this regard, a study was carried out on a particular species of parrots, the parakeets. It turned out that when these birds yawn, the ambient temperature rises.

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Another experiment was conducted on humans. The sample was divided into two groups and each group watched the same video in which images of people yawning were played. The first group had a hot pack on their foreheads and the second group had an ice pack on their foreheads.

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The result? People with the hot pack yawned a lot more than those with the ice pack.

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The function of yawning as a brain thermoregulator could also be found in people who, due to certain conditions, such as anxiety, stroke or multiple sclerosis, experience an increase in internal temperature.

These conditions, according to the Sleep Foundation, cause an inordinate number of yawns, which could be the natural response to internal overheating.

The third and final hypothesis, on the other hand, concerns why yawning is contagious and theorizes that it is an act of empathy.

What has been observed is that contagious yawning occurs mainly when the other yawning person is a family member or a very close person, while it occurs less frequently when the yawning is a stranger or an acquaintance.

This hypothesis is also reinforced by the fact that infectious yawning is almost non-existent in children up to 4-5 years of age. In this period, in fact, mental paths are formed to understand how people feel.

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According to some studies, in which scores were assigned to certain characteristics of a person, it was found that profiles with higher scores in selfishness, insensitivity and other antisocial touches are less likely to yawn than others.

The yawning empathy theory has also been explored in the animal world. It seems that dogs, like people, exhibit a contagious yawn from 7 months of age, when they begin to notice others.

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But unlike humans, emotionality or therefore proximity to a particular person does not affect the contagious yawn of the dog (as it does among humans), a discovery that puts into question the hypothesis of the empathic yawn.

And speaking of contagious yawning ... let's hope you're not yawning right now!

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