What is the phenomenon that makes a person yawn when they’re sitting next to someone who yawns? Try this experiment: Take a big yawn, cover your mouth out of courtesy and watch to see how many people follow suit. There’s a good chance you’ll set off a chain reaction of deep breaths and wide-open mouths. You’ll likely yawn as you’re reading this post too. Just reading or talking about yawning will make you do it, just as seeing or hearing someone else yawn makes us do it, too.
A yawn is a reflex consisting of the simultaneous inhalation of air and the stretching of the eardrums, followed by an exhalation of breath. Yawning (oscitation) most often occurs in adults immediately before and after sleep, during tedious activities, and as a result of its contagious quality.
Why is it that people say they ‘slept like a baby’ when babies wake up like every two hours?
You tossed and turned all night. This meeting is dragging on too long. Your kid just yawned across the dinner table and it’s unavoidably contagious. Usually when a yawn pops up, you know—or think you know—exactly what it means, case closed.
But the scientific side of things isn’t always quite so clear. Long rumored to be a sign of too little oxygen, yawning is actually seen as something totally separate from breathing. In fact, researchers believe the two are actually controlled by separate mechanisms in the body and brain. And while people certainly report yawning when they’re feeling bored or sleepy, there are also those involuntary yawns that seem to have nothing to do with how we’re feeling—like athletes who yawn before competitions or Sasha Obama’s now rather notorious yawn during her dad’s inaugural speech. Heck, you might even be yawning just from reading this. So what do those yawns really mean? Prevention highlights a few things yawns are trying to tell us.
You really like that person. Yawns truly are contagious. Experts believe we may have evolved to catch other people’s yawns as a way of displaying empathy for one another and deepening those social bonds. So it makes sense that further research discovered that yawns are more contagious the closer you are to someone. In a 2011 study, researchers found that yawns were most contagious between family members, followed by between friends, and least contagious between strangers. When yawns did spread between strangers, it took longer for that second yawn to start than when yawns spread between family and friends.
Your brain needs cooling. In the search for a scientific explanation for why we yawn, the latest theory to arise is that yawning basically gives your brain some fresh air—and cools it down. Further supporting this theory was a 2011 study that found that people yawn more during cooler months and less when the outside temperature is warmer. The cooling of the brain would in turn give us the extra energy we need in moments when we let out a big yawn—and because sleep deprivation increases brain temp, we may need extra yawns when we’re sleepy for additional cooling power.
You have a big brain. Apparently the bigger your yawn, the bigger your brain, according to a recent report in the journal Biology Letters. The researchers found that mammals that let out big, long yawns (like, oh, humans!) had heavier brains with a higher number of brain cells. Assuming that yawns do indeed cool the brain in order to energize it, the theory tells us that bigger brains with more neurons would require more oxygen to wake things up, therefore resulting in bigger yawns.
You could be having a heart attack. Or a stroke. Or you might have a tumor. But before you freak: Only excessive yawning, way more yawning than you’d ever expect to produce, is linked to these harrowing health concerns. Heart attacks can stimulate the vagus nerve, which runs from the brain to the abdomen, leading to a reaction that could trigger excessive yawning. Researchers have used MRIs to examine the location of tumors or blockages in the brain, but questions still remain as to how those might disrupt pathways that lead to yawning. People with epilepsy and multiple sclerosis also often report frequent-to-excessive yawning. These conditions (as well as migraine headaches and even anxiety) have been linked to problems regulating brain temperature—so excessive yawning may be the body’s attempt to help out.
Is yawning considered exercise? Many parts of the body are in action when you yawn. First, your mouth opens, and your jaw drops, allowing as much air as possible to be taken in. When you inhale, the air taken in is filling your lungs. Your abdominal muscles flex, and your diaphragm is pushed down. The air you breathe in expands the lungs to capacity and then some of the air is blown back out.