Why we yawn - Brief fact

We all yawn, many know why, many doesn't.
Read, it might orientate you.
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 or indicates that it's time to sleep.
Other people believe that yawning is a protective reflex to redistribute the oil-like substance called surfactant (say: sur-FAK-tint) 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 somewhere, you'll
probably notice a few other people will start yawning, too. Even thinking about yawning can get you yawning.lol.
In summary, this article is just to assure you of the fact you have always noticed that Yawning is contagious.