Yawning cools your brain

Yawning is an unconscious and often contagious action that is still not fully understood by scientists. Yawning is generally associated with the feeling of tiredness or boredom. In these circumstances, yawning causes us to take a deep breath, filling our lungs with fresh air which oxygenates the blood and helps us feel more alert.

However, new research from scientists at Princeton University has now found that yawning also serves as a mechanism to regulate the temperature of the brain. Apparently this is necessary as a cool brain performs better than a warm brain.

Relying on the peculiar tendency of yawning to be contagious, the researchers asked 80 random pedestrians in Tuscon Arizona to look at images of people yawning and then recorded whether they yawned in response. The experiment was conducted both in the summer and the winter so that the effects of air temperature could be assessed.

The findings, which were published in the journal 'Frontiers in Evolutionary Neuroscience', were that that half of the participants yawned in winter while only a quarter yawned in summer.

From this they concluded that one of the functions of yawning is to cool the brain, which may be counter-intuitive as surely you would want to cool the brain by yawning more in summer?

But according to Professor Andrew Gallup, who led the research, yawning cools the brain via a heat exchange with the cooler fresh air. This therefore wouldn't have the same effect on a boiling hot day.

This is the first report to show that yawning frequency varies from season to season and it could help explain why humans become confused and disorientated in extreme heat.

The scientists said that the research could give a better understanding of conditions such as motor neurone disease or epilepsy, where yawning is common.

It also provides a new excuse for yawning. If asked following a yawn: 'Am I boring you?' You can now simply explain that you were cooling your brain!

Published September 2011

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