I have some bad news for you: There’s a good chance that, by the time you’ve finished reading this article, you will have yawned at least once. In fact, if you find yourself yawning a lot while you read this article, don’t be surprised! It’s not because I’m about to bore you (at least I hope not!), but rather because today we’re talking about one of the human body’s most mysterious and contagious functions: Yawning.
But there’s also good news: Yawning may have some surprising benefits.
All About Yawning
Humans yawn all the time for all sorts of reasons. We yawn when we’re bored, sleepy, hungry, and stressed. We yawn when other people or animals yawn. Just reading or thinking about yawning makes us yawn!
When we yawn, it affects almost our whole body. Our mouth opens wide and our jaw drops, allowing for maximum air intake. Our heart rate increases significantly. The diaphragm flexes as our lungs expand. Sometimes we stretch our arms up and out. Then, finally, we exhale, and perhaps consider taking a nap after lunch.
There are two types of yawns: Spontaneous, the kind that seems to come from nowhere, and Contagious, the kind we “catch” from other yawners. While contagious yawning doesn’t usually start until around age 5, spontaneous yawning occurs as early as 11 weeks. That’s right, even fetuses yawn!
But why? The short answer is, we really don’t know. There is no one theory that yet explains why we yawn. The earliest explanation came from Hippocrates around 400 B.C, who believed yawning pulled in “good air” and pushed out “bad air.” Our perspective has changed since then, but not by as much as you might think.
Benefits of Yawning
1. Yawning signals it’s time for a change.
Spontaneous yawns tend to happen when we’re sleepy, bored, or otherwise disengaged from our surroundings. When we yawn, our body gets a fresh influx of oxygen, which can help perk us up. We also yawn during transitional parts of our day, such as right before bed or right after waking. Athletes often yawn before competitions. In other words, our bodies know that change is coming, and is trying to prepare us with fresh blood. The fact that we also stretch when we yawn supports this, as stretching helps increase blood flow.
2. Yawning is a sign of empathy.
Every species of vertebrae yawns spontaneously, but only a handful of species are capable of contagious yawning, most notably dogs and apes, including humans. We are more likely to yawn if we see someone else yawn first. The only exceptions to this rule are people with social difficulties, such as people with autism or schizophrenia. We’ve also discovered that people are more likely to yawn if the person they see yawning is close to them, such as a friend or family member. We also yawn more around people who are socially similar to us, such as people of the same race.
3. Yawning may cool your brain.
There’s a heated debate between whether yawning has a physiological purpose or if it’s purely social. One persistent argument is that yawning may help cool our brains. Yawning draws in a lot of air, which tends to be cooler than our body temperature. It also increases our blood flow, which means the freshly-oxygenated blood gets to our brains faster. Our brains generate a lot of heat, so there may be something to this hypothesis, though there is no definitive proof yet. Still, studies have suggested that a cooler brain may be one possible effect of yawning, if not the primary reason for it.
4. Yawning is a form of communication.
Humans are naturally social creatures. We’ve been living in groups for as long as we’ve been a species. Like we said before, yawning signals the transition to a certain state—like hunger or stress—to ourselves and the people around us. Hundreds of thousands of years ago, knowing whether a member of the group was stressed or fatigued was vitally important to the group’s survival, especially since other members could step up and help the original yawner. Nowadays, yawning mostly just conveys messages like, “I can’t believe we don’t get paid overtime for these quarterly meetings, am I right?”
So, what can we learn from this? While we don’t have a tidy answer that explains all of why we yawn, there are several possible explanations. Knowing these causes gives us an advantage. Now, when you yawn, you can figure out a better understanding of why and act accordingly. The better we understand our bodies, the better we understand ourselves. So, the next time you yawn, thank your body. It’s just trying to help you better understand your current needs!