Why do we yawn?

Almost everyone has experienced it: You're sitting in a meeting, in class, or relaxing on the sofa – and suddenly you open your mouth wide and yawn. Often, the next person follows suit. And then another.

But why do we yawn? Is it really just a sign of tiredness? Or is there a much more complex mechanism behind this seemingly simple reflex?

Scientists have been grappling with this question for decades – and the answers are more surprising than you might think.

Table of contents

1. What happens in the body when you yawn?
2. Tiredness and boredom – the classic triggers
3. Does yawning cool our brain?
4. Why is yawning contagious?
5. Yawning in animals
6. When yawning can be a warning sign
   

7. Conclusion

1. What happens in the body when you yawn?

Yawning is not a "simple" deep breath – it is a complex reflex. Within a few seconds, several processes occur simultaneously in the body.

When yawning:

• We open our mouths wide

• tense the facial, jaw, and neck muscles

• Take a deep breath.

• hold their breath briefly

• slowly exhale again.

This causes a slight increase in heart rate, stimulates blood circulation, and can even activate the tear glands.

All of this happens automatically – controlled by specific areas in the brain, especially the hypothalamus.

2. Tiredness and boredom – the classic triggers

The most well-known explanation is: We yawn when we are tired.

In fact, yawning occurs particularly frequently:

• immediately after waking up

• shortly before falling asleep

• sleep deprivation

• in monotonous or boring situations

For a long time, it was believed that yawning served to increase the oxygen content in the blood. However, this theory is now considered outdated. Studies show that oxygen deficiency is not the actual trigger.

Rather, yawning seems to be a mechanism by which the body tries to increase attention and alertness in the short term – a kind of biological “wake-up call”.

3. Does yawning cool our brain?

One of the most exciting modern theories is the so-called Brain cooling theory.

Our brain produces heat when used intensively – for example, during concentrated work, learning, or under stress. If it gets too hot, performance decreases.

This is where yawning comes into play.

Deep breathing and the altered blood flow could:

• cooler air enters the body

• warm blood is transported away more quickly.

• the temperature in the brain is slightly lowered

Some researchers therefore suspect that yawning functions like a small "reset button" for our brain.

That would also explain why we often yawn before exams, important conversations, or when concentrating intensely – even if we are not tired at all.

4. Why is yawning contagious?

You may have noticed that simply reading about yawning can make you yawn yourself.

Contagious yawning is a particularly fascinating phenomenon.It usually occurs when we:

• to see someone yawning

• Hearing someone yawn

• Just think about it

Interestingly, contagious yawning might be linked to empathy. Studies show that people react more strongly when familiar people yawn – such as friends or family members.

Children only develop this phenomenon in preschool age, a phase in which social skills and empathy are also developing.

This suggests that yawning may not only be a physical reflex, but also a social signal.

5. Yawning in animals

Yawning is not a purely human behavior. Many animal species also exhibit it, including:

• dogs

• cats

• Monkeys

• Lions

• birds

In social animals, yawning appears to serve, in part, as a means of synchronization within a group. When several animals become active or rest at the same time, yawning can be a signal initiating this transition.

It can also occur in the animal kingdom:

• during stress

• in tense situations

• as a calming signal

This shows that yawning is probably an ancient behavior with evolutionary benefits.

6. When yawning can be a warning sign

In most cases, yawning is completely harmless. It is one of the normal bodily reactions.

However, if very frequent or suddenly unusual yawning occurs, it can in rare cases indicate something else, such as:

• chronic sleep deprivation

• severe exhaustion

• Side effects of certain medications

• Stress or overload

Extremely rarely, excessive yawning can also be related to neurological disorders. Therefore, anyone who yawns unusually intensely and persistently, and also feels unwell, should seek medical advice.

7. Conclusion

• Yawning is a complex reflex that can increase alertness and attention.

• It might help to cool the brain down in the short term.

• Contagious yawning is probably related to empathy and social bonding.

• Yawning is an evolutionarily ancient behavior that is also exhibited by many animals.