Yawning: Why and What Could It Mean?

Regulation of brain temperature: The researchers concluded that warmer temperatures provide no relief for overheated brains, which, according to the thermoregulatory theory of yawning, stay cool via a heat exchange with the air drawn in during a yawn.It has been observed that a hot and cold pack on your forehead can change your likelihood of yawning. However, it is more likely that the hot pack induces yawning by decreasing your arousal state, while a cold pack increases arousal and decreases the number of yawns. Your circadian rhythm may also play a role in this.