This Is Why You Yawn

There's a lot more to this everyday phenomenon than you'd think.

About 20 times a day, your jaw expands, your lungs intake a deep gasp of oxygen, and your eardrums stretch taut like guitar strings getting tuned. In other words, you yawn—a lot. And if you're anything like me, you probably do so without giving it a second thought. Let's face it: "Why do we yawn?" isn't a question that crosses a lot of people's minds. But it's one worth examining, because the answers (yes, there are multiple) are fascinating in their own right. Here, organized from "I think I knew that one" to "Really? That's a little bit unsettling," are the most common reasons you yawn.

You're bored.

Yeah, yeah, the oldest excuse in the book is actually the truest excuse in the book. According to Bill Fish, a certified sleep coach and co-founder of Tuck, the sleep information site, there are many reasons why your body requires you to yawn—and most of them actually don't pertain to how much sleep you got the night before. For one, a yawn could simply be sending the signal to others that you're bored. In fact, according to a study conducted by Temple University, we tend to yawn more when stimulation is lacking. So, basically, when you're bored out of your mind, your brain tries to keep your body alert and attentive despite feeling bored or fatigued.

You're tired.

Duh. But a deep dive reveals that it's more interesting than simply that. While many believe that yawning is a symptom of poor sleeping habits, that's actually not entirely the case—though it can contribute to the reason, according to a group of researchers at the University of Vienna. In their study, they deduced that the real reason people yawn is to reduce the brain's temperature—and since sleepy bodies have a harder time regulating core body temperatures, temperatures tend to rise more quickly, enforcing the need for a few yawns to ease our bodies into a colder realm.

You saw someone else yawn.

Fact: yawning is contagious. Even among other animals—like dogs, wolves, and primates—a yawn can be almost impossible to escape when you watch someone else engage in the act. This copycat effect was laid out in a study in The Psychological Record, where participants yawned more frequently when asked to read literature about yawning, versus those who just read about scratching or daydreaming.

You're stressed.

Even when you're feeling stressed and on high alert, your body can still instigate a few yawns that may undoubtedly feel out of place, says Fish. And, while not much formal research has been done on the correlation between yawning and anxiety, many researchers note that even dogs yawn when feeling anxious. Yawns are often introduced as a way to keep the brain alert and awake—traits that are necessary to possess to barrel through stressful circumstances. (By the way, excessive yawning is even considered a "suspicious passenger behavior" by the TSA—so keep your nerves in check the next time you go through airport security.)

You're hungry.

Since hunger, like exhaustion, can also effectively heighten the temperatures in the brain, we're more prone to yawn when meal time rolls around. An easy trick for combatting these yawns: snack every few hours throughout the day. And to make sure you're not incurring any negative health effects in the effort to tamp down your yawns, keep the snacks light and healthy: apples, carrots, hummus—that sort of thing.

You've just endured a hard workout.

Since the comedown from a tough workout can affect your body and brain, yawning can be a useful mechanism for the brain, as it can help ease your body into a state of ease, according to Robert Provine, a neuroscientist at the University of Maryland, Baltimore County, and author of Curious Behavior: Yawning, Laughing, Hiccupping, and Beyond. "Right after waking and before bedtime, which is consistent with yawning's role in facilitating state changes: sleep to wakefulness, wakefulness to sleep, arousal to de-arousal, or vice versa," he told Wired.

You're getting a migraine.

If you're experiencing yawns at a more increased interval, it might be the first symptom of a migraine coming your way. This is all according to Angie Glaser, content editor of Migraine Again, a digital community for people who suffer from migraines, and author of the blog Chronic Migraine Life. "Yawning is a common sign that the first stage of a migraine, called the prodrome, is already happening in the brain. Before the pain phase starts, about 75 percent of people with a migraine will experience symptoms like fatigue, moodiness, and food cravings. That fatigue leads to lots of yawning—and is a clear clue that it's time to take medication or find a place to lie down before the migraine attack gets any worse," she says.

Your brain needs to cool down.

In another scientific endeavor, your yawns are actually able to increase the blood flow in your neck and face, along with the large inhale giving a boost to your body's cycle of blood and spinal fluid. These changes pertain to another key element of our yawns, presented by the aforementioned University of Vienna study. During that study, researchers actually found that participants were more likely to yawn in temperatures around 20º Celsius (that's 68º Fahrenheit), since, according to the researchers, this temperature was hot enough for participants' brains to signal a cool-down of the brain.

Your blood needs oxygen.

To get scientific, yawning always plays a part in the body's respiratory functions, giving an influx of oxygen to your blood and helping to clear it of any toxins. So, if you're not breathing as much as your body would like, yawns are designed to help bring oxygen to your oxygen-deprived blood.

You might have a sleep disorder or brain condition.

If you find that your yawning is excessive, especially to the point where it causes the muscles in your neck, face, and jaw to hurt, then it may be a symptom of a sleep disorder or brain condition. When the vagus nerve—the part of your nervous system that connects the throat and abdomen to the brain—is experiencing a reaction, it can either point to the fact that your brain seems to have its signals crossed, or that perhaps a sleep disorder is causing extreme fatigue throughout your body. In any case, get thee to a doctor to make sure.

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Ashley Moor
Ashley hails from Dayton, Ohio, and has more than six years of experience in print and digital media. Read more