What causes a yawn

The Yawning Mystery

Yawning has been perplexing people since time immemorial. Namely, we all know that we usually yawn when we are tired or bored. However, not many of us know why this happens. Rather, there have been many theories about this phenomenon, some more plausible than the others. Either way, we are still puzzled by the whole yawning issue, not knowing which theory to believe in. If you belong to the group of people interested in looking further into yawning, perhaps the following lines will make the whole process understandable and logical enough.

The Yawning Speculations

We know that yawning is an involuntary action, mostly affecting us when we are bored, sleepy and tired, as well as in some other, similar situations. Taking into consideration that our yawning sequence involves rapid inhaling followed by exhaling, there are theories that yawning is connected to oxygen and carbon dioxide exchange in our organism. Namely, once our oxygen levels drop, our organism triggers yawning in order to make us intake more oxygen into the blood stream. However, some scientists claim that we breathe in much less oxygen while yawning, than we do through actual breathing, making this theory lack practical reasons.

There are several other beliefs, considering yawning to be a process taking place due to the need for pressure balancing in both of our inner ears. Also, some people believe that we yawn in order to cool our brain down, since it got warmer due to us feeling tired and sleepy.

Furthermore, there are theories that yawning takes place in order to provide us stretching or clear our lymphatic systems. Moreover, yawning is thought to be triggered by certain chemicals in our brain, or be a clear indication of us being hungry and our glucose levels dropping.

Another interesting theory connects our yawning to our distant cousins, animals. Namely, some scientists presume that animals communicate through yawning. They use the contagious aspect of it in order to transfer information. For example, knowing that one animal yawning can trigger the same effect in other animals, they can use this phenomenon as a signal for danger. Subsequently, our distant evolutionary heritage may include this aspect as well, explaining the connection between our yawning triggering other people's yawning etc.

Finally, ancient Greeks and some other old cultures thought that yawning signifies us being abandoned by our soul. Thus, all people were advised to keep their hand over the mouth in order to keep the soul inside. However, this was probably introduced for hygienic, cultural and aesthetic reasons too.