Does this all seem familiar? Yawning is an interesting behavior that is being done not only by humans, but also by animals. Most people assume that yawning is brought about by boredom or exhaustion. Others don’t know why they yawn, but when they see someone else yawn first, they just come help it and and yawn too.
Although scientists still cannot tell the exact mechanisms of a yawn, they agree that it is an involuntary reflex that controls the oxygen and carbon dioxide levels in the blood.
What is a yawn?
Technically speaking, a yawn is a reflex wherein the individual opens his mouth and inhales deeply, followed by a slow exhalation. This is one among the many involuntary reflexes managed by the nerve and spinal centers.
Why yawn?
Many scientists believe that the beginning of a yawn is due to fatigue or boredom. One reason behind yawning is thought to be the increase in the concentration of carbon dioxide or low levels of oxygen in the blood or lungs, especially the alveoli of the lungs. So, yawning is a reflex action that helps the body to increase the intake of oxygen into the lungs and consequently to the bloodstream. However, many researchers do not regard this as a satisfactory explanation, as according to them, oxygen intake is less while yawning than during normal respiration.
Another reason why we yawn is because yawning controls the temperature of the brain and thereby helps in cooling the brain. It generally occurs when one is tired or has not had enough sleep, as both these conditions have been found to increase brain temperature. While some believe yawn to be a mechanism to cool the body, others think, it occurs to stabilize pressure on either side of the eardrums. Yawning is also regarded as an action quite similar to stretching, as it also flexes the muscles and joints of the body, besides increasing blood pressure and heart rate.
Effects of Yawning
When you yawn, the sudden rush of oxygen into your system increases your heart rate and eliminates the carbon dioxide buildup in the lungs and blood stream. Oxygen is also brought to the brain. Yawning ventilates the lungs and restores normal breathing. Thus, many people believe that yawning is the body's reaction to the lack of oxygen in our body.
Is Yawning Contagious?
A yawn is contagious, in the sense that it can easily spread to the person who is observing the other person yawning. Besides observing, even reading or thinking about it is also found to stimulate yawning in some individuals. Some are of the opinion that it may be caused by mirror neurons present in the frontal cortex of the brain, which imitates the action of others. These neurons get activated when exposed to a stimulus or action performed by another individual usually from the same species. As yawning keeps the brain cool and alert, it is also thought to be an evolutionary development, through which a group of animals can be kept alert and vigilant against possible danger. Many researchers also believe that yawning is an empathic behavior that happens naturally. Contagious yawning is also considered to be a herd instinct used to communicate tiredness and time to sleep, to other individuals in a group.
Thus, yawning is not only associated with tiredness, sleepiness and some physiological conditions, but is also a form of non-verbal communication that can be interpreted to mean several different things. Apart from these, it has given rise to some really interesting beliefs or superstitions. To the ancient Greeks and Mayans, yawning was a sign which indicated that the soul of the person yawning was trying to run away from the body. Another common belief is that one should always cover the mouth while yawning, otherwise the soul may escape from the body. These beliefs may have originated to discourage public yawning, and also to maintain public health, as yawning might facilitate the spread of diseases.
Reflections
I feel that yawning is rather common in our lives. However, many people who do not know the mechanism behind yawning. For example, when a teacher sees her student yawning, she would automatically assume that her students is feeling bored of her lessons. Thus, her reaction would be to scold the student. She does not know that we yawn because of a lack of oxygen and not really because of her lesson. Therefore, these people should really do some online research before jumping to conclusions. The teacher should actually get the facts right before even punishing the students. It would be an embarrassment if the teacher herself is a Science teacher... Also, it is basic courteousy to cover your mouth when you yawn as the expression on your face would look horrible. So, next time when you feel like yawning in class, you better turn around and cover your mouth to avoid getting caught by the teacher!
If you are reading this article and you're a teacher yourself, please do the right thing by forgiving the student who has yawned in your class.
