the number 13

Need To Know: Why Yawns Are Contagious August 9, 2009

Filed under: Need To Know — numbr13 @ 12:02 am



You’re probably yawning right now, aren’t you.

People always laugh about this and many wonder why this happens. It’s a phenomenom many don’t understand and few (ahem…. me) will actually do the research to share the facts with others around them (ahem…. you).

Some animals yawn out of hostility as a threat. Other animals yawn as a mating ritual. However, when human beings yawn it’s for more physiological reasons involving imbalances in the oxygen and the Co2 in the air around us and in our bloodstreams.

A nerve in our brainstems trigger our bodies to react when there are higher quantities of Co2 in the air around us. As a reflexive reaction, we yawn, sucking in huge, gulping breaths of fresh oxygen as we simultaneously stretch. Both of these actions cause oxygen to be pumped forcefully through our bloodstream and act as a coolant on the hypothalmus causing us to become more alert and more aware.

The result of this action is to exhale large quantities of Co2 out of our bodies that then circulates the air around us and can cause other’s the immediate need to yawn as well.

But then there are those weird times when we yawn simply because we’re witnessing it from afar, see it on television, hear someone else yawn or even have to read the word over and over again in some chick’s blog post. This is considered an empathetic reaction and is triggered because our minds are being alerted of the whole imbalance in the air situation and our bodies are reacting to the danger imposed by it.

When you get tired or bored and daydreamy, your breathing slows. You take smaller inhalations but exhale more deeply, most of the time without even noticing it. This produces a “pocket” of Co 2 around you that you continue to inhale which creates the imbalance in your bloodstream.

This is also the cause of cribdeath in most cases. Babies will sleep with blankets or with faces to the side or even facing down and it’s not that they are suffocating but they are exhaling Co2 into tiny folds in sheets and blankets that they are then forced to breath in for an extended period of time. Their blood gets poisoned and they die for what seems to be no reason at all. It’s craziness.

For us adults, it’s all psychological and it’s simply another way that our bodies were made to be thriving, surviving machines. We can’t see or understand what threatens the air around us (unless you live in Los Angeles) but our bodies know and it tries to protect itself. By…. yawning! One yawn sends out the signal to other bodies and they yawn, too. So, our blood is cleansed, our brains are cooled off and our circulation is improved.

Fascinating, huh?