Why Do We Yawn?

Did the title of this blog post make you yawn? It’s okay. We’d be lying if we said writing it didn’t make us yawn a couple times too. Everybody yawns because it’s a biological need, not just because we’re feeling bored and tired.

The theory behind yawning is that it serves as a thermoregulatory process to cool down the brain. The human brain uses a lot of metabolic energy—cheers to us for being thinkers—which means it tends to heat up more than our other organs. To cool it, yawning triggers blood flow to the brain to draw the heat away from your skull. A cooled brain means you’re able to stay more alert and your cognitive functions are able to perform better.

Our bodies are constantly changing states of energy and alertness throughout the day depending on a number of factors like the time of day, the activities you’ve been up to, and the quality of your sleep, just to name a few.

Temperature regulation has a lot to do with why yawning often happens when we’re transitioning from being asleep to being awake.

In an article by the Smithsonian, Andrew Gallup, a psychology professor at SUNY College, says that: “Before we fall asleep, our brain and body temperatures are at their highest point during the course of our circadian rhythm.” By yawning, our temperatures decline.

When we wake up, our brain and body temperatures rise more rapidly than at any other point during the day because of the energy it requires. A good yawn can expel all the heat, cooling down our brains so that we stay more alert and are better suited to effectively tackle the day ahead.

Now for the question you’ve been waiting for: Is yawning contagious? The answer: Technically no, but human empathy plays a huge part in whether you catch another person’s yawn. Just like how we’re likely to laugh when a friend is laughing or feel fear and concern with another person, yawning from witnessing a yawn is the simple practice of empathy, and it’s more likely to happen if we have a closer connection to them.

So if you yawn when you see someone else yawn, kudos to you, empathetic human. We could use more of you in the world.