why do people yawn?

Answer 1

when a person yawns, it is due to the lack of supply of air to the body due to fatigue or tiredness. a person yawns to get in more air for respiration for energy to be released.

Answer 2

Everybody yawns — from unborn babies to the oldest great-grandparent. Animals do it, too. But why, exactly, do people and animals yawn? No one knows for sure. But there are many theories (ideas) about why people yawn.

One is that when we are bored or tired, we just don't breathe as deeply as we usually do. As this theory goes, our bodies take in less oxygen because our breathing has slowed. Therefore, yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood.

Yawning, then, would be an involuntary reflex (something we can't really control) to help us control our oxygen and carbon dioxide levels. Sounds good, but other studies have shown that breathing more oxygen does not decrease yawning. Likewise, breathing more carbon dioxide does not increase yawning. Hmmm. Now what?

Another theory is that yawning stretches the lungs and lung tissue. Stretching and yawning may be a way to flex muscles and joints, increase heart rate, and feel more awake.

Other people believe that yawning is a protective reflex to redistribute the oil-like substance called surfactant (say: sur-fak-tunt) that helps keep lungs lubricated inside and keeps them from collapsing. So, if we didn't yawn, according to this theory, taking a deep breath would become harder and harder — and that would not be good!

But there is one idea about yawning that everyone knows to be true. It seems contagious. If you yawn in class, you'll probably notice a few other people will start yawning, too. Even thinking about yawning can get you yawning.

Answer 3

Brain is lacking oxygen and needs more so we yawn to get a nice big lung full of the stuff. Normally occurs when we are tired because the tired body doesn't pump the oxygen in our blood as efficeintly.

Answer 4

Because when we are tired, we slump and therefore less oxygen gets into our lungs when we breathe, then our body reacts to that and makes us yawn in order to get more oxygen back into our system.

Why we yawn when we see other people yawn, though, is another matter entirely, and I don't know the answer to that one!

Answer 5

Tired and fatigued people start shallow breathing .After sometime this shallow breathing keeps more carbondioxide in lungs and less oxygen gets inside blood through lungs. As a reflex arrangement one or two deep breathings in and out balance the gases. This is commonly called yawning

Answer 6

Sometimes it is because they are sleepy or tired. Sometimes it may be even because that person is lacking oxygen so a huge breath comes in the form of a yawn.

Answer 7

apparently when there is a dip of oxygen in the blood, we breathe in extra hard (Yawn) to get oxygen to the brain quicker.
when we see others yawning, psychologically we panic and think there is not enough oxygen in the atmosphere (or something like that) and therefore yawn too.
it made sense to me when it was first explained but its a bit fluffy now - sorry xxx

Answer 8

Boredom. Tiredness. If we were animals a yawn with the eyes open is a threat (see how big and how many teeth I have, so stay away). Maybe we can do that too!

Answer 9

You yawn coz ur tired this way your bringing more air into your body - more oxygen to provide more energy - but think it doesnt work as it makes me feel more tired

Answer 10

ACTUALLY YAWNING IS A VERY EXCITIN MECH OF OUR BODY TO GET RID OF TIREDNESS. V FEEL TIRED WHEN V HAV NO SUFFICIENT OXYGEN IN OUR BODY. BY YAWNIN, MORE O2 IS TAKEN INTO SO THAT V R REFRESHED BY THE RELEASE OF ENERGY..