What is the cause of yawning?

Answer 1

Here are two basic reasons:

a.) To get more oxygen into your lungs (and therefore into your body)
b.) Believe it or not, yawning also helps you relax. If you ever feel tense or anxious, you can try to make yourself yawn and it will help.

Answer 2

We don't know. The favored theory in the past was that yawning provided more oxygen to your system to help increase dwindling energy. But recent studies have shown that has a neglible effect on oxygen levels in the blood.

The current theory is that it is a hold-over behavior from the ancient days when humans were little more than nomadic apes. When the group started yawning, it was a signal to the leader that it was time to stop for the night. This might also explain why yawning seems to be contagious, if someone at the back of the group started yawning it would be "passed aong" until the pack leader noticed.

Answer 3

Your body needs more oxygen - thus triggers the yawn. When we're sleepy we often breathe less efficiently - thus why yawning often happens then.

But.........why is it that yawning is contagious?

Answer 4

oxygen if u notice you breath a big breathe when you yawn because your brain needs oxygen thats why u snore u breathe heavier in your sleep so your brain gets oxygen if u stayed outside you would never yawn or go to sleep

Answer 5

you yawn so that you can get more oxygen to the brain..I believe

Answer 6

Your body's need for air.
But....how does that explain contagious yawns? Does EVERYONE need air?

Answer 7

For example, I yawn when I read a boring question whose answer is everywhere on the internet. http://www.howstuffworks.com/question572.htm

Answer 8

Yah, you probably need more oxygen in your body. If your body has too much or there's an imbalance, you get the hiccups.

Answer 9

Lack of O2 in the system

Answer 10

lack of oxygen to the brain