Thermoregulation Yawning cools the brain

Yawning is supposed to cool people's brains

05/12/2014

People yawn because they are tired or bored. Researchers from Austria and the US have now found another reason for the yawn: It should serve the thermoregulation to cool the brain.

Yawning should serve the thermoregulation

05/12/2014

People yawn for a variety of reasons: because they are tired because they are bored or because they are under stress. Researchers from Suny College, New York and the University of Vienna have now identified another reason for yawning. It is therefore the thermoregulation, to cool the brain. Sleep cycles, cortical states of excitement and stress are characterized by fluctuating brain temperatures. According to the scientists, yawning should compensate for these differences. They concluded that, according to this theory, and assuming that low air temperatures result in less heat in the brain, yawning should be easy to manipulate by ambient temperature.

Yawning frequency in Vienna and Arizona compared
To test this hypothesis, Jorg Massen and Kim Dusch from the University of Vienna examined the „contagious“ Yawning frequency of pedestrians in Vienna in both summer and winter months. Subsequently, they compared the results with those of a previous study in the arid climate of Arizona. The passers-by in Austria were asked to look at a series of pictures of yawning people and to report their reactions. The scientists published their findings in the journal „Psychology & Behavior“.

Depending on the optimal ambient temperature
The researchers came to the conclusion that while the people in Vienna yawned more in the summer than in the winter, this was exactly the opposite for the US subjects. It turns out that neither the season itself nor the number of hours of daylight is decisive, but that „contagious“ Yawning is mainly dependent on the optimal ambient temperature around 20 degrees Celsius. With the high summer temperatures of 37 degrees in Arizona and the temperatures around the freezing point in Vienna, therefore, the yawning provoked by others decreased. Study author Massen concludes from this observation: „Yawning as thermoregulation for the brain can not work if the ambient temperature and body temperature are the same. At ambient temperatures around the freezing point, this is also not necessary - or even dangerous.“

Yawning to relax
Moreover, as a statement from the University of Vienna indicates, while there is a general assumption that yawning increases oxygenation, previous studies have failed to confirm a connection between yawning and elevated levels of oxygen in the blood. However, it is known that yawning is one of several recommended exercises to relax when you have tired and dry eyes. In fact, it is very easy and effective to start moistening and cleansing the eyes. The eyes are wet and the burning disappears again. (Sb)