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Why Do We Yawn?

Biology | 7-14 yrs | Interactive, Learning Pod

Have you yawned when you are bored and sleepy in class? You sure have! Have you noticed how people around you start yawning after you yawn? So, that would make yawns contagious. This is one of the many theories about why we yawn. Watching someone else yawn, seeing a photograph or reading about, and even the mere thought of yawning, it is said, is enough to make you yawn.

What is a yawn?

Technically, a yawn is the reflex opening of the mouth followed by the deep inhalation and slow exhalation of oxygen. This behavior is under involuntary control and cannot be consciously controlled or suppressed. So, when you gotta yawn, you gotta yawn.

Why do we yawn?

Even though yawning is such a common activity – you yawn, your dog yawns, your cat yawns – the reasons behind this large gaping of the mouth are still not fully understood. There are many theories about why we yawn. Like that include boredom, tiredness and because someone else is doing it. Earlier, yawning was believed to be a biological mechanism in humans and primates such as apes and chimpanzees, to keep the brain from overheating.

Does yawning make you alert?

The popularly believed theory about yawning is that it is a respiratory reflex, which regulates the carbon dioxide and oxygen levels in the blood. It is believed that when our breathing is shallow and little oxygen is being supplied to the lungs, the sudden intake of oxygen by yawning increases your heart rate. It also rids the lungs and the bloodstream of the carbon dioxide buildup and forces oxygen through blood vessels in the brain while restoring normal breathing and ventilating the lungs. As a result of this, one’s alertness is heightened when one yawns. However, this theory falls short because it does not explain why people who have a high level of oxygen in their blood also yawn.

Is yawning useful to us in any way?

Another theory is that yawning stretches the lungs and lung tissue. Some scientists say that yawning is a protective reflex to redistribute the oil-like substance called surfactant that helps keep lungs lubricated and from collapsing. This means that if we didn’t yawn, taking a deep breath would become harder and harder. So the next time someone yawns when you are talking, don’t feel offended. They are just regulating the oxygen in their blood or stretching their lungs!

I’m sure you must have yawned reading this too!

The first theory of yawning was that it precedes a fever and is a way to remove bad air from the lungs. Who came up with this theory ?