What Causes us to Yawn?

We usually yawn when we are tired, want to sleep, or are bored. It is usually an involuntary action. The reason and purpose of yawning are unknown, but may be related to a lack of oxygen. If you find that you yawn frequently, you can try to breathe consiously using full, deep inhalations and exhalations and then check to see how you feel. Increased oxygen in the blood stimulates all systems of the body to perform optimally.