Why We Yawn

Yawning is not due to lack of oxygen in the brain as previously thought, but due to a temperature regulation activity, according to a 2014 study. This helps explain why we yawn less in the winters.

We yawn when we are tired or bored, as the brain slows down, causing the temperature to drop. We also yawn when the body wants to wake itself up, stretching out the lungs and tissues and pumping blood towards our face and brain.