Why Do We Yawn?

Hippocrates, a respected physician from ancient Greece, believed yawning helped you rid your body of sickly air. A more likely explanation for why you yawn is that your brain is hot.

Yawning brings colder blood into your skull, which has a cooling affect/effect on your brain. Why would you want that? Because brain temperature affects/effects how alert you feel. When your brain gets too warm, you feel drowsy. 

Now, you could dunk your head in a bucket of ice to perk yourself up—but why do that when a hearty yaaaaawn will do the trick?

The affect/effect of yawning on the body isn’t well understood. Until recently, it was thought that we yawn when we’re sleepy to refresh ourselves with a jolt of oxygen to the bloodstream. It turns out that’s probably not true. Research has not shown that yawning affects/effects the amount of oxygen in the blood. One possible reason for why we yawn when we’re tired is that our brains are warmer right before and after we sleep. 

How many times have you yawned while reading this? Seeing a yawn, reading about a yawn, or just thinking about a yawn can trigger one. No one is sure why other people’s yawns affect/effect us this way. Some researchers believe it has to do with empathy. Studies have shown that you’re more likely to catch a yawn from someone you care about than from a stranger. But if you yawned looking at this page, then you know: Even the yawn of a kitten or a giraffe can affect/effect you!