Why do we yawn?

Yawning is something that all humans (and many other animals, including birds, reptiles, and fish) do regularly. Even babies in the womb can yawn. But what is the reason behind this yawning? Many of us think that yawning is something we do when we are tired, but it may not be that simple. Yawning is one of our most basic behaviors.

Several factors may play a role in your yawning. Here are some of the most common ones:

There are five reasons to yawn:

1) Fatigue

2) Social impact

3) Stress

4) The brain overheats

5) Hunger


1) Fatigue:

One theory is that when our body owes sleep and is too tired, we do not breathe deeply and deprive the body of the essential oxygen that helps us function best. As an involuntary reflex, spontaneous yawning forces us to open our mouths wide, stretch our jaws, and take deep breaths to help us receive oxygen and clear our bodies of carbon dioxide.

Just keep in mind that research is not conclusive. Another theory is that yawning and breathing are controlling by two completely different mechanisms.

Some studies seem to point to yawning as an involuntary reflex that stimulates your brain to become more alert. You are taking deep breaths to shoot oxygen into your brain. Yawning is also related to the secretion of hormones that briefly increase your level of consciousness and heart rate. One study found that a big, deep yawn acted like caffeine. That could be an evolutionary response designed to prevent sleeping by our ancestors to prevent predators from invading.


2) Social impact:

Some researchers believe that when we yawn we are communicating with each other but we do not know what the connection exactly is. Some scientists believe that contagious yawning may be an old connection or social bond that goes back even before humans spoke.

From an evolutionary point of view, yawning is likely to be a signal to synchronize behavior among group members in the past, as if everyone were sleeping together at the same time for safety. Our yawns can also be a way to communicate with the group that they also need to yawn to wake up and be aware of the danger.

We are not the only ones who yawn in response to the yawns of others. Mammals (as well as very social animals) do the same. particularly, Chimpanzees,  have shown this tendency. There is even some evidence that if your pet dog sees that its owner is doing this, it may respond.


3) Stress:

Have you ever yawned before a stressful event?

If you have this experience, know that you are not alone. Researchers have found a link between yawning and stress. but, they still do not understand why exactly it occurs. Your body seems to know something important is on the way, so it rushes to you to prepare. The reverse can also be true. Yawn as your brain slows down from overstimulation. Yawn!


4) When the brain becomes too hot:

One theory proposed by researchers is that involuntary yawning may act as a cooling mechanism for the brain. It is similar to the internal air conditioning of our body. Yawning creates enough tension in your jaw, which increases blood flow to the head, neck, and face. Deep breathing accompanied by a big yawn also forces spinal fluid and blood to flow down our brains. The cooler air we breathe through our mouths helps to cool those liquids. All of these systems work together to clear warmer fluids from the brain while pushing coolant upwards.


5) Hunger:

An interesting theory holds that yawning can be caused by low glucose levels in the brain, meaning that we can yawn when we are hungry.

There are some signs that dehydration may cause you to yawn more than usual. When we are hungry, we feel tired and weak, which can lead to yawning. Interesting fact: it has been shown early humans yawn more when they are hungry.