Yawning is a normal reflex that probably helps the body shift between feeling sleepy and feeling more alert. It is common when someone is tired, bored, or less focused, and it does not seem to happen just because the body needs more oxygen.
A yawn involves a deep breath, stretching of the face and jaw muscles, and brief changes in heart rate and breathing. These changes may help the brain and body become more awake. Some research also suggests yawning may help cool the brain slightly, while other studies suggest it may help keep the upper airway more open.
Yawning can also be contagious, so it is normal for one person’s yawn to trigger another. In most cases, yawning is harmless. When it happens very often, especially with loud snoring, poor sleep, or daytime tiredness, it may be worth looking into possible sleep problems. Learn more about what can cause extreme fatigue and how to treat it.
If yawning becomes excessive or appears with other symptoms, the safest step is to speak with a primary care doctor. It is also important to avoid self-medicating with stimulants or supplements before the cause is clear.