Yawning: seeing as it’s probably one of the most overlooked daily rituals of almost all vertebrates, who knew that it could play such a vital role in ensuring so many of our bodily functions are carried out properly? This article will delve into the ‘whys’, ‘whats’ and ‘hows’ behind this seemingly mundane act, as well as the many unanswered perplexities that still puzzle scientists to this day, so I hope you save your yawns for afterwards.

 

First and foremost, yawns are an involuntary reflex that requires the coordinated movement of thoracic muscles in the chest, the diaphragm, larynx in the throat, upper spine and the palate in the mouth all working together to inhale and exhale a large volume of air. The movement is built into our human code - babies learn how to do it as young as 20 weeks old. But it’s not just for humans - all vertebrate animals carry out this function but one outlier: Giraffes. This is because their heads are simply too far from their hearts and lungs so they have special adaptations to their circulatory and respiratory systems that negate the need to yawn. 

 

By yawning we distribute surfactant, a secretory product composed of lipids and proteins, across the surface of our lung’s alveolar walls to coat the alveoli in order to boost the efficiency of its function to carry out gas exchange in our respiratory system. 

 

Not only this but yawning can also stretch out our joints and muscles as part of our pandiculation system which is crucial to maintaining lower tension levels in our soft tissues. 

Additionally, the act of sharply inhaling a large volume of air naturally quickens our heartbeat which then leads to a domino effect of causing the rate of circulation of blood and spinal fluid through the body to increase therefore increasing alertness. 

 

One theory behind yawning is that it serves a thermoregulatory function where this whole process may be a way to cool down a brain that has gotten too hot. 

 

Another theory which is less scientifically backed than the first one is that it allows our bodies to draw in more oxygen, however, according to a team of researchers from SUNY college New York, a relationship between these two processes has not yet been confirmed.

 

As for why we yawn, there are many different circumstances and they’re explained through a lot more science than you might think. For example, one might yawn when they’re feeling tired because their brain is slowing down its activity, causing its temperature to drop. Therefore, we could be using yawns as a way to improve circulation. However, as mentioned earlier, this has yet to be proven. Similarly, yawning could be due to feelings of boredom seeing as our brains aren’t being stimulated enough, causing a temperature drop. Another question posed by yawns is why they’re contagious. The answer to this is that because of a phenomenon known as echopraxia, people are subconsciously inclined to mimic certain behaviors, including yawning.

The bottom line is that although scientists have yet to back up many of the theories mentioned here, yawning actually serves purpose beyond letting others know when to stop droning, ranging from pandiculation to thermoregulation to even increasing alertness, ultimately keeping us vertebrates happy and healthy.