Yawning helps keep the brain cool, and the sinuses play a role in that process by acting as bellows, a new report suggests.
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.
Researchers at the University of Albany in New York said their experiments showed that raising or lowering oxygen and carbon dioxide levels in the blood did not produce the yawn reflex.
In a study of the 44 students, researchers found that those who breathed through the nose rather than the mouth were less likely to yawn when watching a video of other people yawning.
Putting Your Yawns to Work
- To stimulate better thinking. When you are preparing for an exam, a presentation or an important conversation, you can enhance your performance by yawning several times first. During an exam, don't be shy about yawning when you find yourself losing focus or starting to stumble in your thoughts -- it will help.
- To reduce jet lag and reset energy levels. At 20 weeks gestation, fetuses start to develop a wake/sleep pattern and as part of the process, they yawn... a lot. We can consciously use yawning to help reset our wake/sleep patterns, including when suffering jet lag. To start, yawn five times or so as soon as you get off the airplane. When you've experienced how well this refreshes you, you may soon begin to do it intuitively -- you'll find yourself yawning whenever you feel yourself starting to drag. Yawning can be used in this manner to help you acclimate to high altitudes and to reset your energy level as you switch from one activity to another, such as from sleep to wakefulness.
- To improve your mood... and, possibly even your relationships. Yawning is associated with increased levels of dopamine, the neurotransmitter released from the hypothalamus that is associated with pleasure, motivation and sociability.When two people yawn together, it can help diminish tension in the relationship... and fortunately, yawning is highly contagious, so it's easy for both of you to get in on the act. If nothing else, a shared yawning session should make for a few ice-breaking laughs.
- For relaxation. Curiously, although yawning serves to stimulate the brain, a deep yawn and wide stretch also relax the body. Lind-Kyle, who leads meditation classes, always starts with a healthy yawn, which she says gets people relaxed quickly. She said that bringing on a few deep yawns at bedtime may help you get to sleep.
"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.
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.
The paper appears in the December issue of the journal Medical Hypotheses.