Why Do People Yawn?

A yawn is a reflex consisting of the simultaneous inhalation of air and the stretching of the eardrums, followed by an exhalation of breath. It is a very natural response of being tired. But have you ever wondered why people do it? Well, here goes! Firstly, no one knows for sure, but there are many theories about why we yawn. One theory is during boredom and tiredness, (usually when it occurs) we don't breathe as deeply as we usually do. As this theory goes, our bodies take in less oxygen into the blood and move more carbon dioxide out of the blood; so we yawn.

Another recent study says that “yawning suggests that it exists to cool down the brain. That open-mouthed yawn causes sinus walls to expand and contract like the bellows, pumping air into the brain; which towers it’s temperature,” (huffingtonpost.com.)

A third theory out there is that yawning stretches the lungs and lung tissue. They think that maybe, stretching and yawning is a way to flex muscles and joints, increase your heart rate, and overall feel more awake.

The last theory I will be sharing is a bit different than the others. Other people believe yawing is a reflex to redistribute the oil-like substance called surfactant that helps keeps your lungs lubricated inside and keeps them from collapsing. So according to this theory, if we didn't yawn, taking a deep breath would become harder and harder - and that would not be good! As you can see, there are multiple ideas of why we do this. And there's probably more and more to come in the future, maybe even a proven reason.