What Causes Yawning? .

Yawning is often considered a sign of laziness. We don't like it when someone yawns in front of us. However, it's normal for a tired person to yawn. Scientists haven't been able to pinpoint the exact cause of yawning, but some studies have concluded that when a person is tired, their muscles relax, and their breathing rate decreases. A person needs to breathe in about 6 to 7 liters of air per minute to get enough oxygen. If a tired person can't take a full breath, they get less oxygen. The brain needs more oxygen. As soon as oxygen decreases, the brain starts to become sluggish. When drowsiness sets in, the brain immediately sends a message to yawn, signaling to take in more air through the yawn. A yawn lasts for 5 to 6 seconds, and a deep breath is taken. During this time, your eyes and ears stop working. You might have experienced not being able to hear while yawning. Thus, yawning is a physical action to bring the body back to alertness. We also consider it a sign of sleepiness.