Yawning isn't triggered because you're bored, tired or need oxygen. Rather, yawning helps regulate the brain's temperature, according to Gary Hack, of the University of Maryland School of Dentistry, and Andrew Gallup, of Princeton University.
"The brain is exquisitely sensitive to temperature changes and therefore must be protected from overheating," they said in a University of Maryland news release. "Brains, like computers, operate best when they are cool."
During yawning, the walls of the maxillary sinuses (located in the cheeks on each side of the nose) flex like bellows and help with brain cooling, according to the researchers.
Function of sinuses
They noted that the actual function of sinuses is still the subject of debate, and this theory may help clarify their purpose.
"Very little is understood about them, and little is agreed upon even by those who investigate them. Some scientists believe that they have no function at all," Hack said in the news release.
The researchers said their theory that yawning helps cool the brain has medical implications. For example, excessive yawning often precedes seizures in people with epilepsy and pain in people with migraine headaches.
Doctors may be able to use excessive yawning as a way to identify patients with conditions that affect temperature regulation.
"Excessive yawning appears to be symptomatic of conditions that increase brain and/or core temperature, such as central nervous system damage and sleep deprivation," Gallup said in the news release.
(HealthDay News, November 2011)