Why do we yawn?
Why is yawning so contagious? What causes our body to yawn? I’ve been taught that yawning is your body’s attempt to rebalance your oxygen & carbon dioxide levels in your blood. In other words, if you hadn’t been breathing efficiently, you’ll body will want to reset by taking a yawn. And that is one potential explanation. However I have recently learned that yawning could be caused by many things and there isn’t a scientific consensus as to why we yawn.
We all yawn. As humans, we start yawning as a 12 week old fetus, we will continue to yawn into old age. Some people yawn a lot, others yawn just occasionally. The average human yawns 9 times/day. And it’s not just humans, most vertebrates including fish also yawn. If you yawn, your dog or a nearby chimpanzee is likely to also yawn, suggesting that yawning can be contagious across species.
Yawning is more complex than simply opening the mouth and breathing in deeply. The entire airway is dilated and the muscles are stretched, particularly around the larynx. The exhale tends to be quicker and muscle tension is released and sometimes we make vocalize or make a sound as we exhale. Yawning may be more a response of the nervous system than the respiratory system. Yawning holds both physiological and social functionality. Below is my understanding of the latest theories about why we yawn.
Why do we yawn?
To create arousal. We yawn when we’re sleepy and need to be alert.
To adjust pressure in the middle ear. You’ll often do this on the airplane.
During circadian rhythm transitions. We yawn most transitioning between wake & sleep.
During drug withdrawal. Much yawning happens during opioid withdrawal.
To match others. Seeing, reading, or talking about yawning increases yawning frequency.
To help the body regulate temperature. To help the brain and body cool down.
Personally I used to be a heavy yawner – definitely yawning more than 9 times/day, probably yawning more than 9 times in an hour. About 15-20 years ago, something shifted and now I rarely notice a yawn. I’m not sure what happened. I breathe through my nose much more now (I used to be a mouth breather). I probably am a little more rested and emotionally balanced, it’s hard to say exactly what changed. However I do find it very interesting that I used to consider myself a “yawner” and now I don’t.
Yawning is something that our body’s do to take care of us and help keep us alive and thriving. Yawning is some form of self-regulation and social connection. And exactly what triggers a yawn in your body is still a mystery. In the meantime, know that you are not alone, animals have probably been yawning since the at least the age of dinosaurs.
