People usually yawn when tired. In theory , provide additional energy to evaporate . However , this theory has been refuted by studies that showed that people who need more oxygen ( including sport and people with medical conditions depriving oxygen ) not as much evaporation of the people in general .
Yawning is still a mystery . A psychologist at Georgia Gwinnett College Lawrenceville , Ga. , Steven M. Platek , Ph.D. , ferreting yawning can be contagious .
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" Brain size of a grapefruit but consume 40 percent of energy metabolism . Runs hot and brain , " Platek said as reported by HuffingtonPost , Wednesday ( 04/16/2014 ) .
Researchers have found that yawning cools the brain , preventing it from overheating, which can reduce alertness . Temperature increases brain intimate when we are tired and when we are bored .
" The temperature of the brain determined the three- variable rate of blood flow in the arteries , blood temperature and metabolic heat production in the brain , " writes Andrew C. Gallup , Ph.D. , assistant professor of psychology at SUNY College at Oneonta .
According to him , yawning serves to increase arterial blood flow and allowing blood flow to the brain cooler . To answer the question about what happens in the body is quite simple . When yawning , mouth open and breathe deeply, and ends with a short breath . During that time , the muscles around the brain to contract and stretch and you take out the air . Then , in cold blood in the push towards the skull while the warm blood is pushed out .
" This action increases the blood flow to the brain and the skull and brain at the same time , it forces the warm venous blood away from the skull , " said Gallup .
Secondary behavior such as arm stretch or move your head when yawning serves as a cooling technique in the area under the arm . Moreover , the whole body stretching prepares your muscles for quick action , contribute to encourage vigilance that comes from the brain temperature is cold .
When evaporated heartbeat you can take as much as 30 percent and yawning is a sign of arousal , including sexual desire . Many other body parts that work when vaporized .
First , open your mouth , and your jaw drops , which allows air to enter as much as possible . When you inhale , the air taken to fill your lungs .
Your abdominal muscles flexible and your diaphragm is pushed down . The air you breathe expands lung capacity and then some air is blown back .
In the results of the study in Frontiers , Neuroscience , Gallup and his colleagues found that Omar T. Eldakar brain temperature rise was preceded by yawning in humans and mice . They also discover how to yawn more frequently when the ambient temperature is high .
Much research has focused on contagious yawning . This is a phenomenon in which we respond to evaporate others also do so . What’s more , we tend to evaporate when a close friend or family member do it .
Most of the studies say yawning is contagious. From an evolutionary standpoint , this makes sense .
" If one member of the group evaporates , it indicates something you should be doing , " Platek said .
Interestingly , people with autism or schizotypal personality disorder often do not evaporate .
So why do you yawn ? It could be to cool the brain that work hard or to increase alertness or just because you saw someone else do it .