Yawning is so contagious that even the thought of writing about it is making me gasp for air like an athlete training for the World Yawnathon Championship. And the reason why I can confess to this apparent lethargy at work is because this week I learned from very reliable sources it doesn't get better than Princeton researchers reporting in the journal Frontiers in Evolutionary Neuroscience - that yawning is not a sign of a bored or tired mind, but a mind that is overheated.
While I choose to interpret an overheated mind as one pushed close to the atrophic state due to overwork, my colleaguses appear unconvinced. But even these sneering cynics cannot ignore the science behind the research that confirms that yawning is the body's way of instinctively cooling down the brain when the head starts to heat up. When the ambient air is cooler than your supercharged gray matter, yawning works as a natural thermostat by allowing the cooler air to rush in and bring the brain back down to a comfortable temperature.An overheated brain makes you drowsy and tired, which explains why humans become confused and disorientated in extreme heat as the brain has limited ways of cooling itself down. It also explains why excessive yawning usually precedes and accompanies severe headaches and migraines, as it precedes sleep, when brain temperature is the highest.
Interestingly, yawning works only when the surrounding temperature is cooler than the body, which explains why the body falls back on other ways to regulate temperature in summer, such as sweating.
Apart from ambient temperature, the amount of processing the brain is doing, the temperature of the blood and the rate at which it flows to the brain also influence its temperature.
The human brain, with its 100 billion cells roughly the number of stars in the Milky Way forging one quadrillion connections, has reason to be very,very tired. Brain cells last a lifetime, which makes them among the oldest cells in the body. Even in the sleep mode, nerve impulses carrying information travel to and from the brain along the spinal cord to monitor and regulate body processes, such as digestion and breathing and to coordinate body movement.
It's constantly on overdrive to control sense perception and memory. Its two hemispheres work in tandem, the left focusing on sequence, literalness and analysis, and the right on context, emotional expression and synthesis. Since the basic blueprint for vision, language, memory and emotions progressively evolve by how we choose to use the brain, it never switches off till we die.
The brain's cooling mechanism is the same across species. Previous research, again from Princeton University, shows that bringing down the ambient temperature induces yawning in birds and rats, suggesting it is a physiological function other than general tiredness.
While I admit to wondering how much researchers yawned working on this apparently redundant study when they could have had their pick of deviant behavioural anomalies, the importance of the work cannot be ignored. Now millions of bored students and employees can disguise their disinterest as overwork and yawn their way through brain-addling lectures and meetings. Who knows, yawning may even replace IQ as the test for intelligence. With the World Yawnathon Championship so close to reality, I have to take a break now to focus on some serious training.