Yawning is a common reflex in which you open your jaw wide, take a deep breath, and then quickly breathe out. It lasts 4-7 seconds and often happens when you’re waking up or falling asleep. Yawning begins in the womb as early as the 11th week of pregnancy and continues for a lifetime. When you yawn, a wetting agent known as a surfactant coats the tiny air sacs (alveoli) in your lungs, which helps keep them open. Although no one knows exactly why we yawn, new studies suggest that yawning may not always be a sign that you’re tired or bored, as most people believe. Interestingly, many people feel more relaxed after yawning. As for why you yawn, there are several reasons, including the need to equalize the pressure in your ears when flying, because you’re tired and your brain needs to be alert, because your brain needs cooling during exercising, and as a side effect of certain anti-anxiety medications. Yawning is usually not bothersome, except when it happens too frequently in a short time. Consider seeing a doctor if it bothers you or if sleep problems are causing you to yawn often.
