Friday, 19 Dec, 2008 Health & Fitness

Why People Yawn


In most cases, yawning is associated with tiredness and boredom. Newly, it has been proved that a yawning person does not try to show lack of interest, but, on the contrary, just tries to catch your attention.

One of the main causes of yawning was established by a group of scientists under the leadership of Andrew Gallup from Binghamton University, Animal Behaviour magazine reports.

The cause was the overheating of the brain –its outrunning of a certain critical temperature.

The American scientists have made a study on a group of parrots, as representatives of vertebrates. These birds have a relatively big brain, they live in Australia where a frequent temperature variation is a normal thing, and the most important fact is that "catching yawning" (characteristic for humans and some animals) is not characteristic for this species of birds.

The parrots were put into 3 different conditions: a raised temperature, high temperature and regulated average temperature. When zoologists started increasing the temperature from its average value, the frequency of birds' yawn increased by two times.

It results that if the human brain is overheated, it's the most probably that, in a very short time, he or she will yawn. This physiological act resembles the work of a fan that cools the overheated processor of a computer.

Now it's clear why people frequently yawn before and after sleeping (the brain needs cooling and recovery), also why sometimes yawning can be a symptom of a disease.

Yawning is usually associated with tiredness. Suppose a person is tired and wants to sleep, in such conditions the temperature of the brain is raised, so is the temperature of the blood that irrigates it.

A frequent yawning is one of the symptoms of diffuse sclerosis and attack of epilepsy. In addition, frequent yawning is characteristic to people suffering from migraines. Insistent yawning can be a sign of problems linked with temperature regulation in the brain. This means that doctors should be more attentive to patients complaining from attacks of groundless yawning.

Posted by summer_rain

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