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Health July 2013

Aid for Age

Here’s a Real Yawner

By Tait Trussell

Some people cover their mouths when they yawn. Some don’t. There was a time long ago when yawning was considered a matter of life and death. For centuries, most people thought that covering your mouth prevented evil spirits from entering your body.

 

I will bet you can’t read this without yawning.

Not that it’s that boring. Actually it is rather fascinating.

Before you finish reading this, it's likely you'll yawn at least once. Don't misunderstand, I’m not intending to bore you. The fact is: just reading about yawning will make you do it, just as seeing or hearing someone else yawn makes us do it, too.

Well, what's behind this mysterious need to yawn? First, yawning is an involuntary action that causes us to open our mouths wide and breathe in deeply.

We know it's involuntary because we do it even before we're born: According to Robert Provine, a developmental neuroscientist at the University of Maryland, research has shown that 11-week-old fetuses yawn. And while yawning is commonly associated with relaxation and drowsiness, it is said that your heart rate can rise as much as 30 percent during a yawn.

It’s an act of common courtesy to cover the mouth when yawning. But some people cover their mouths when they yawn. Some don’t. There was a time long ago when yawning was considered a matter of life and death. For centuries, most people thought that covering your mouth prevented evil spirits from entering your body.

In those early days, doctors even thought the common tragedy of infant mortality was attributable to babies yawning, according to author Charles Panati. (And, of course, babies didn’t cover their mouth when they yawned.)

Roman doctors urged mothers to cover their babies’ mouths when they yawned to protect them.

Yawning is an involuntary action that causes us to open our mouths wide and breathe in deeply. Anything involuntary is not in our control, as you know.

There are many parts of the body that are in action when you yawn. First, your mouth opens and jaw drops, allowing as much air to be taken in as possible. When you inhale, the air taken in is filling your lungs. Your abdominal muscles flex and your diaphragm is pushed down. The air you breath in expands the lungs to capacity and then some of the air is blown back out.

Some years ago, researchers proposed that yawning is used to cool the brain. They also discovered that people yawned more often when they pressed a warm or room-temperature towel against their heads than when they pressed a cold towel against their heads. People who breathed through their noses (thought to reduce brain temperature) did not yawn at all in the experiment.

It is possible that yawns are contagious because at one time in evolutionary history, the yawn served to coordinate the social behavior of a group of animals. When one member of the group yawned to signal an event, all the other members of the group also yawned. Yawns may still be contagious these days because of a leftover response not used anymore.

We know that much of yawning is due to suggestibility -- it's infectious. You don't need to actually see a person yawn to involuntarily yawn yourself; hearing someone yawn or even reading about yawning can cause the same reaction. Chances are you'll yawn while reading this article.

Scientists aren’t sure why we yawn. Sleepiness or fatigue are possible reasons. Others say we yawn to get a breath of reviving oxygen. Other people instinctively see that some oxygen has been removed from the air, and they yawn to replenish the oxygen they feel was taken out of the air.

Other reasons indicate that yawning or even reading about yawning seems to be a simple reflexive reaction to a subconscious desire to empathize with the person who’s yawning. It appears that there is some relationship between yawning and our ability to “put ourselves in other people’s shoes.” However, not all people can “catch” a yawn when they see someone else yawning and these people also appear to be less able to understand things from other people's points of view. This may be a skill for being able to get along with others, letting you understand how they feel. So yawning maybe is just a by-product of our being able to use our own experience to understand how others feel. Or maybe it's due to accidental “cross-wiring” in the brain that occurs when the thinking-about-others part of the brain is stimulated.

Nobody really knows.

If you haven’t yawned by now, I’ll bet you will before the day is over.

 

Tait Trussell is an old guy and fourth-generation professional journalist who writes extensively about aging issues among a myriad of diverse topics.

Meet Tait