According to a 2015 article in Scientific American, yawning provides a special service to the brain. What does a good yawn do?

According to the article, when you yawn and therefore breathe in deeply, this provides incoming air to cool the brain. Additionally, stretching the jaw increases blood flow to the brain too, which also cools it. The warmer blood in the brain is replaced by cooler blood from the heart.

Asked by Tom Cohen · Last updated 5 years ago · 2.8K views