The not so boring reasons for yawning

From fact to fiction, yawning has fascinated most of us for the numerous reasons behind it.
Now a new study has found that the primary purpose of yawning is to control brain temperature.
If your head is overheated, there's a good chance you'll yawn soon.
The finding solves several mysteries about yawning, such as why it's most commonly done just before and after sleeping, why certain diseases lead to excessive yawning, and why breathing through the nose and cooling off the forehead often stop yawning.
The key yawn instigator appears to be brain temperature.
"Brains are like computers," Andrew Gallup, a researcher in the Department of Biology at Binghamton University who led the study, told Discovery News. "They operate most efficiently when cool, and physical adaptations have evolved to allow maximum cooling of the brain."
He and colleagues Michael Miller and Anne Clark analyzed yawning in parakeets as representative vertebrates because the birds have relatively large brains, live wild in Australia, which is subject to frequent temperature swings, and, most importantly, do not engage in contagious yawning, as humans and some other animals do.
Contagious yawning is thought to be an evolved mechanism for keeping groups alert so they "remain vigilant against danger," Gallup said.
For the study, the scientists exposed parakeets to three different conditions: increasing temperature, high temperature and a moderate control temperature. While the frequency of yawns did not increase during the latter two conditions, it more than doubled when the researchers increased the bird's ambient temperature.
A paper on the findings has been accepted for publication in the journal Animal Behavior.
If air in the atmosphere is cooler than brain and body temperatures, taking it in quickly cools facial blood that, in turn, cools the brain and may even alter blood flow. Prior studies reveal yawning leads to a heightened state of arousal, so a morning yawn may function somewhat like a cup of coffee in providing a jolt of energy.
The new findings also explain why tired individuals often yawn, since both exhaustion and sleep deprivation have been shown to increase deep brain temperatures, again prompting a yawn-driven cool down.
In the future, researchers may focus more on brain temperature and its role in diseases and their symptoms. But the new study on yawning changes the popular notion that yawns are mere signs of boredom.

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