What Causes Yawning?

Yawning is considered a sign of laziness. We generally do not like it when someone yawns in front of us. However, it is a normal occurrence for a tired person.
Even scientists haven't been able to identify the exact cause of yawning, but after some study, it has been concluded that when a person is tired, their muscles relax, and their rate of breathing decreases. A person needs to inhale about 6 to 7 liters of air per minute to get sufficient oxygen. If a tired person cannot breathe deeply enough, they get less oxygen. The brain requires the most oxygen. As soon as oxygen levels drop, the brain starts to feel sluggish and drowsy, prompting it to immediately send a signal to trigger a yawn and inhale more air.
A yawn lasts about 5 to 6 seconds, taking in a deep breath. During this time, the eyes and ears temporarily pause their functions—you may have experienced that you stop hearing while yawning. Thus, yawning is a physical process meant to refresh the body. We also consider it a sign of impending sleep.