Anatomy And Physiology

Why we Yawn



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Some of the functions of the human body are enigmas wrapped in conundrums. For example, what causes that mind-numbing pain of brain freeze when you eat ice cream too fast? What causes hiccups? Why do we yawn, especially if we see someone else yawn?




These are weighty subjects and you deserve some answers. Pronto!




I don't care how sophisticated you might think you are, at some point in time, you yawn. It might be behind closed doors, or you might try and stifle it by keeping your mouth closed while you cheeks strain to let that baby out, but you yawn. We all do.




There. I've said it. Now that this dirty little secret is out in the open and we've admitted it, the next step is to understand why we yawn. It's actually a very interesting story.




I learned about the yawn one afternoon during a particularly boring meeting around a client's conference room. Somebody was droning on and on, ad infinitum about the third quarter numbers not meeting expectations, or something equally scintillating. BTW, this self-important mumbler is no one that you know. He/she is not anyone I work with now, nor anyone who might want to give me a big, fat performance bonus. Got that? If you are a current colleague, client or friend, this is not about you! It was some other boring, bag of wind.




As I was staring at my laptop, pretending to take copious notes of what was being imparted by this sad excuse for a communicator, I happened upon an article by Heidi Dawley who writes good stuff for medialifemagazine.com. Her piece was entitled "The real truth about yawns."




Turns out, the yawn is not a sign a sign of boredom. Nope. The real purpose of a yawn is to cool the brain. Whenever we open that big Boca to yawn and that fresh air comes rushing in, the brain gets a refreshing shot of this. Heidi talked to scientists and they agreed that the fresh, cooler air invigorates the brain, allowing it to better focus on whatever matter is at hand. Including, but not limited to the adverse impact of the third quarter numbers!




So, rather than a rude sign of boredom, the yawn can be seen as an expression of interest.




In a related study, professor Gordon Gallup from the psych department at the State University of New York in Albany noted that yawning is as natural as scratching our heads. It begins before we are born and it is also common among many animals.




Mr. Gallup added that the idea of yawing cooling the brain arises from the fact that the old noodle uses lots of calories to operate, about one-third of our caloric intake, and this kicks off lots of heat. "Brains are like computers, notes Prof Gallup. They can operate efficiently when they are effectively cooled."




Side bar: If the brain is burning those kinds of calories, why aren't we trying to think out way out of this obesity crisis?




But, I digress.




Apparently, when a person's brain temperature becomes too elevated, it triggers a yawn. When the poor schlub yawns, large volumes of cool air pour into the lungs, cooling down the blood in the capillaries. This causes the heart rate and blood pressure to increase and this in turn sends a cool wave to the brain. Et voila', a cooler brain.




So, what about the phenomenon of contagious yawning? You see someone else yawn and you have an urge to do the same. Gallop tested this "cooling the brain" theory on a few (no doubt, bored) grad students. He showed them video of people yawning and instructed them to breathe through their noses or hold a cold pack to their heads. He found that the yawning stopped while the participants were engaged in these brain cooling techniques.




There's also a theory about how contagious yawning got started. In the cave-dweller times, vigilant watching was important for group safety. Nod off and some wooly mammoth would take a bite outta your backside. So, if someone yawned it would have shown that the person's brain was performing at a "suboptimal level" (that's a little anthropological term to see if you're still awake). A big ol yawn all around could have helped ensure that the group maintained vigilance.




So, the next time someone bores you to tears or you've been trying to cram an entire semester's reading assignments into one night, go ahead and let out a giant yawn. It's cool for the brain.

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