Why Do You Yawn? (It's Not What You Think...)
by Joseph Mercola: The
Everyday Drink That May Contain Blood, Pus, and Drugs
Yawning is an involuntary behavior that may perform
the important function of cooling your brain
When you yawn, the influx of cool air may ventilate
your sinuses and facilitate brain cooling
Brain temperatures increase when you’re sleep deprived,
which may be one reason why exhaustion triggers excessive
Yawning may also indicate a capacity for empathy, and
may be an evolutionarily old process of great social
is usually associated with boredom or being tired, but new
research suggests there's far more to this behavior than meets
clue that yawning serves a much greater purpose?
it involuntarily, like breathing, and it starts even
before we're born (as early as 11 weeks after conception).
are a number of theories out there for why we yawn, but one
of the most compelling is being explored by a Princeton University
researcher and his colleagues, whose studies suggest yawning
performs the important function of cooling your brain.
Keep Your Brain Cool
in Animal Behaviori
explains the hypothesis that "yawning serves as a thermoregulatory
mechanism that occurs in response to increases in brain and/or
hypothesis further stipulates that, as ambient temperature
increases and approaches (but does not exceed) body temperature,
yawning should increase as a consequence."
previous research by Andrew C. Gallup, PhD, now a postdoctoral
research associate at Princeton University, and colleagues
revealed that frequency of yawns more than doubledii
among parakeets when their ambient temperature increased.
this time on humansiii,
also showed that more people yawned when it was winter compared
to when it was summer (45 percent versus 24 percent, respectively),
which supports Gallup's theory that people should yawn more
in cold weather because the cool air you inhale helps regulate
your brain temperature.
are like computers... They operate most efficiently when cool,
and physical adaptations have evolved to allow maximum cooling
of the brain."
it simply, it's theorized that the influx of cool air that
occurs when you yawn helps cool and increase blood flow in
your neck, face, sinuses and head, which together acts like
a radiator to cool your brain. Writing in the journal Medical
Gallup and colleagues suggest this process may also involve
your sinuses (the actual function of which is also up for
posterior wall of the maxillary sinus may flex during yawning, operating
like a bellows pump, actively ventilating the sinus system, and
thus facilitating brain cooling. Such a powered ventilation system
has not previously been described in humans, although an analogous
system has been reported in birds."
finding is in line with previous research that shows brain
temperatures increase when you're sleep deprived, which may
be one reason why exhaustion triggers excessive yawning. Gallup
also suggests that excessive yawning may even be a symptom
of health conditions that increase brain and/or core temperature,
such as central nervous system damage.
Yawning Have Social and Cognitive Implications, Too?
theory for why we yawn revolves around its social, rather
than its physiological, effects. It's known, for instance,
that yawning is contagious among humans, chimps and even dogs,
a behavior that is thought to indicate a capacity for empathyvi.
In the journal Frontiers of Neurology and Neurosciencevii,
it's suggested that:
contagious yawning is a primitive expression of social cognition,
namely empathy. Susceptibility to contagious yawning is correlated
with the speed in recognizing one's own face, theory of mind
processing, and is also associated with activation in regions
of the brain that have been associated with social cognitive
processes. This suggests that contagious yawning may be an
evolutionarily old process that begot a higher level of social
cognition in certain species."
has even been associated with arousalviii
or a change of state, such as going from being alert to sleepy
or vice versa, according to Dr. Robert Provineix,
a neuroscientist at the University of Maryland. For now it's
safe to say there's much more to be discovered about exactly
why virtually all mammals yawn, but in the event you feel
you yawn excessively, be aware that it could have physiologic
implications. At the very least, it might mean that you could
use a good night's sleep, in which case you can review my
sleep aid secrets.
It could also
be caused by a vasovagal reaction, which is caused by the action
of the vagus nerve (the tenth cranial nerve that runs from your
brain stem down to your abdomen) on your blood vessels. This could
be a sign of a heart problem and should be checked out by your health
care provider. Excessive yawning may also occur before a seizure
in people with epilepsy, or prior to the onset of a migraine, so
keep this in mind if you suffer from either.
2012 Dr. Joseph Mercola
Best of Joseph Mercola