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Why do we yawn?

Biology | 7-12 yrs | Interactive, Learning Pod

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 behaviour cannot be consciously controlled.

Why do we yawn and why is it contagious?

The many theories about why we yawn 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?

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 our heart rate and alertness. However, this theory does not explain why people with a high level of oxygen in their blood also yawn.

Is yawning useful to us in any way?

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.