Even thinking about yawning can cause you to do it. It’s something everybody does, including animals, and you shouldn’t try to stifle it because when you yawn, it’s because your body needs it.
You yawn when you’re:
– Tired: Your brain is slowing down, causing its temperature to drop
– Bored: Your brain isn’t feeling stimulated and starts to slow down, causing a temperature drop
– Seeing someone else yawn: When you’re in the same environment as them, you’re exposed to the same temperature
Another reason you may yawn is because the body wants to wake itself up. The motion helps stretch the lungs and their tissues, and it allows the body to flex its muscles and joints. It may also force blood toward your face and brain to increase alertness.