by Jacob Puhr

Everyone yawns. In fact, while writing this sentence I yawned.  But why?  We all know that when we’re tired and bored we find ourselves yawning.  Once again, I’ve yawned while talking about why we yawn, and now I’m yawning once more.  The more I find myself yawning non-stop while writing about yawning non stop, I wonder why?  Believe it or not scientists lack a shared, definitive consensus of why we yawn.  

Instead of answers, theories are proposed as to why we yawn.  The seemingly most accepted one is that yawning regulates brain temperature.  When yawning, blood flow increases.  As this flow increases, heat is more capable of dissipating and our eyes water which releases heat.  Sleep Foundation referenced, in one article, several studies that revealed when participants placed a warm pack on their heads, they yawned more than those with a cold pack.  On top of those studies, another showed that people yawn more during summer than winter, also adding evidence to the theory we yawn in warmer environments to help cool the brain.

The other theory proposed is that the brain yawns in order to awaken the brain.  When your body yawns, your neck arches back and your mouth opens up.  As this occurs, the carotid arteries, blood vessels that send blood to the brain, become stimulated.  With the increased blood-flow, the heart beats faster and you stay awake.  The motion of yawning causes lungs and tissues to stretch and muscles to flex, so your body is trying to stay active in a way.  Scientists may say it’s no coincidence that we usually yawn only when we’re tired, so it’s plausible we yawn during these tiresome periods to give our body a jump start so to say.   

As to why yawning is contagious, one answer is given.  By seeing others yawning, our own brain may, without us noticing, recognize if someone else is yawning, then our environment is too warm, so we should yawn too.  This theory suggests yawning is an empathetic response and several studies support it.  We begin to yawn around the age of five, when we’re able to understand how others in our environment are feeling.  The closer we are to a person, the more we yawn, implying we yawn more around those we emphasize the most with; those who tested higher for empathy scores were found more likely to yawn more.    

After reading this article, don’t feel too tired.  You may just yawn.