Why Do You Think We Yawn When We Feel Sleepy Or Drowsy?
Abstract: Some evidence suggests that yawning is a means of communicating changing environmental or internal body conditions to others. Still, low oxygen levels in the paraventricular nucleus (PVN) of the hypothalamus of the brain can induce yawning. Another hypothesis is that we yawn because we are tired or bored.
Still, low oxygen levels in the paraventricular nucleus (PVN) of the hypothalamus of the brain can induce yawning. Another hypothesis is that we yawn because we are tired or bored. Once stimulated, the cells of the PVN activate cells of the brain stem and/or hippocampus, causing yawning to occur
When you feel sleepy. it is actually the brain cells that are in a sense of saying..going to fall asleep for lack of oxygen (hypoxia or hypoxemia). Also when we feel drowsy, our respiratory rate being controlled by reflex centers in our brain falls. This is a vicious cycle. The yawn breaks this cycle.
- One of the more obvious reasons for yawning is we do it when we are tired. The deep breath associated with yawning helps us to draw in more oxygen and supply the much-needed oxygen to the tired body organs including the brain. However, this theory has been challenged by some studies.
- The social role of yawning is to express boredom.
- Yawning being contagious have also led researchers to hypothesize that yawning represents a sign of shared empathy. fMRI imaging has also shown that the centers of the brain that are activated during yawning are the precuneus and posterior cingulate gyrus, which are the centers responsible for our ability to “put ourselves in other's shoes”. Mirror neurons also play a significant role. People having problems with social communication like those with autism and schizophrenia display less contagious yawning.
- Yawning helps to arouse us. When boredom sets in and we cannot maintain or attention, yawning kicks in and is accompanied by an increase in heart rate, skin conductance, and EEG changes
- To cool the brain- “The contraction and relaxation of facial muscles during a yawn, increases the facial blood flow which subsequently aids in the dissipation of heat through the emissary's veins. The gaping of the mouth and deep inhalation of cool air during a yawn also alters the temperature of blood going from the lungs to the brain via convection. Tearing from the eyes, which some people experience, at the peak of yawn may likewise play a role in a dissipation of heat from skull”. Further, the frequency of yawning also seems to increase with an increase in body temperature or ambient temperature.
- To equalize pressure in your brain- As it occurs when we climb altitude such as during an airline trip.
- Yawning is even seen in fetuses and many vertebrates like cats, dogs chimpanzees, etc. It is a primitive act and has evolutionary significance, rather than just an external manifestation of boredom.
