YOUR HEALTH - MEDICINE 101

YAWNING

Believe it or not, the study of yawning is very exciting! I know - you think yawning is just boring, tedious, ho hum - right? (yawns!) Excuse me. Wrong! Yawning is a very complex physiological activity whose purpose is not completely understood.

We start yawning when we're just an apple in our mother's eye. On an ultrasound, we can see infants as young as 12 weeks yawning in the uterus. And it's one of the first things we do as newborns. On average we adults yawn about ten times a day - the most common times are when we first wake up and just before hitting the sack. Olympic athletes yawn before their competition and paratroopers yawn before they jump.

Yawning is an all or nothing experience - just try and stop in the middle of one. A complete yawn lasts about six seconds. - contrary to popular belief, yawning does not improve oxygenation of the blood.

You'd think with that wide opening of the mouth and the sucking in of air that yawning would be seen more frequently in situations where there is lower oxygen content in the air we're breathing, but its not so. Nor does the rate of yawning increase if we increase the amount of carbon dioxide in the air around us.

Yawning is of course very contagious. Watching someone else yawn often triggers the impulse in you. Reading about yawning causes you to yawn. Even watching television while someone yawns makes you feel like yawning and of course if you yawn in somone's face while they're talking, it sends a clear social message - you're bored. In lower animals yawning may have a different message - Siamese fighting fish yawn before they attack each other. Gorillas and other primate yawn and bear their teeth as a sign of aggression.

So why do we yawn? Some researchers think yawning is like stretching. Both increase blood pressure and heart rate and flex muscles and joints. Stretching the jaw and face muscles is necessary for a good yawn .. just try one with your mouth closed. Doesn't really work. But the more popular belief is that yawning is a physical phenomenon that reflects a mental state of decreased arousal or boredom. The physical movements that come about as a result of yawning don't have a specific purpose - just like the movements of smiling, grinning, laughing or crying do not have a specific physical purpose. All they're doing is communicating your mental state to those around you. If you're happy you laugh. If you're sad you cry. If you're bored, wearied or apathetic you yawn, sending a clear signal to those around you.