Dr Hannah Brown, aka Dr ScienceLover, has been in I’m A Scientist Organ Zone for just over a week. Hannah has had some great questions – one of which was ‘why are yawns contagious?’
Hannah gave a great answer and here it is!
“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”
To view Hannah’s profile click here!