Everybody yawns, let it be newborn baby, teenager or grandparent. Even animals do it. But no one knows why we do it.

However, there are many reasons and theories about it. People do not do it only when they feel sleepy but at times out of tiredness or dryness of the throat. Science suggests that when one feels so, it is due to the dearth of oxygen. It’s because when our breathing becomes slow then yawning helps us to inhale more oxygen into the body and exhale more carbon dioxide from the blood. Another leading reason and accepted theory is that yawning stretches lungs and lung tissues. Hence, yawning may be a way to flex muscles and joints so as to increase the heart rate. If we do not yawn, then taking a deep breath would become harder and harder and that would not be good for the health. The scientifically backed and approved theory about why we yawn is brain temperature regulation.

A 2014 study published in journal physiology behaviour looked at the yawning habits of 120 people and found that it occurred less during winter. If the brain temperature gets too far outside of the norm, inhaling air can help cool it down. There is one idea that everyone knows is true that yawning seems contagious. If you yawn in class or anywhere you will surely notice a few other people start doing it too. Even thinking about yawning can make you yawn. It’s a fact of the matter that you can’t escape yawning once you think of it.