Yawning stretches the lungs and rib cage muscles. It may also increase your heart rate. These actions taken together may help boost your alertness.
Yawning is a sign your brain or body is changing states. People often yawn before bedtime, when becoming bored, or after exercising. That’s led researchers to believe yawning plays a role in transitioning from one state to another.
Yawning is a social cue and response. Why is a yawn contagious? This may be the answer. Yawning is a way people signal one another about their state of alertness. If you yawn after someone else does, you may be demonstrating empathy for them.
