Why do we yawn when tired?
Show answer & explanation
Answer: To cool the brain
To get more oxygen — Wrong. This is a common misconception. Research shows blood oxygen levels don't change significantly with yawning. The current theory focuses on brain temperature regulation.
To cool the brain ✓ — Correct! Recent research suggests yawning helps cool your brain. When tired, your brain heats up slightly. Yawning brings cool air into your nasal and oral cavities, which cools blood going to the brain. This helps keep your brain at best temperature for functioning. That's why yawning often happens when drowsy or in warm rooms.
Tiredness releases yawn chemicals — Wrong. There's no 'yawn chemical' released by tiredness. Yawning is triggered by the brain's need for cooling, not by special chemical signals. The physical act brings cool air to regulate brain temperature.
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