if yawning is caused by the brain’s need for oxygen, how does that relate to being tired?


if yawning is caused by the brain’s need for oxygen, how does that relate to being tired?

In: Biology

Excess CO2/insufficient O2 is just one proposed cause of yawning, and we still don’t know for sure what it does, what causes it, or why it’s such a conserved trait among mammals.

In terms of fatigue for some species, it’s believed to play a role in signaling tiredness to the herd, so everybody can synchronize their sleep schedules together. But again, we don’t know for sure.

It’s thought by some to be a combination of multiple functions which would explain why it’s such a highly conserved trait- it’s versatile.

Yawning can be caused by the brain needing oxygen but that is not the only possible cause of yawning. A lack of oxygen does cause you to become tired which is one of the things that can trigger yawning. The yawning might increase the oxygen in our blood which will releave some of the tiredness caused by lack of oxygen but will also cause you to wake up a bit, if only temporarily. This is however just a possible explanation for why we yawn when tired and it is not actually improving the oxygen levels in your blood by a lot so it may not be a good reason. However yawning is a very common social signal not only among people but also other social animals. It is also contaious so you may start to yawn when you see others do it. So it might have started as some way of releaving the lack of oxygen or making you wake up but it have evolved into more of a social message.

When a person is at rest, like sitting on a couch, their breathing slows and becomes shallower as they dont need as much oxygen. When they get up, engage in conversation, or do anything that requires more energy then the body needs more oxygen for the increased function. Yawning is associated with being tired as people tend to be active throughout the day and not slow down until close to bedtime so yawning is seen as being tired. But if you’ve ever sat through a long lecture, or spent most of the day laying on the couch then you’ve probably yawned without necessarily being tired. It’s simply a way your body transitions from an inactive time to an active time.