Subject: Why Do We Yawn
So this goes a long way toward explaining why we in the Northern States are so,o,o,o much smarter than our Southern neighbors.
And now that we can be consumed with worry that our next yawn indicates that our brain is too hot, or that we are about to have a stroke or heart attack, perhaps we might begin a study of the common belch...or the meaning of excessive farting.
Carl Jarvis
----- Original Message -----From: J.RaylSent: Friday, April 20, 2012 5:34 AMSubject: [acb-chat] Why Do We YawnBy Dr. Mercola
Yawning is usually associated with boredom or being tired, but new research suggests
there's far more to this behavior than meets the eye.
The first clue that yawning serves a much greater purpose?
We do it involuntarily, like breathing, and it starts even before we're born (as
early as 11 weeks after conception).
There 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.
Yawning Might Keep Your Brain Cool
A study in Animal Behavior
i
explains the hypothesis that "yawning serves as a thermoregulatory mechanism that
occurs in response to increases in brain and/or body temperature.
The brain-cooling hypothesis further stipulates that, as ambient temperature increases
and approaches (but does not exceed) body temperature, yawning should increase as
a consequence."
Indeed, previous research by Andrew C. Gallup, PhD, now a postdoctoral research associate
at Princeton University, and colleagues revealed that frequency of yawns more than
doubled
ii
among parakeets when their ambient temperature increased.
New research, this time on humans
iii
, 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.
He told Discovery News
iv
:
"Brains are like computers... They operate most efficiently when cool, and physical
adaptations have evolved to allow maximum cooling of the brain."
To put 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 Hypotheses
v
, Gallup and colleagues suggest this process may also involve your sinuses (the actual
function of which is also up for debate):
"The thin 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."
This 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.
Does Yawning Have Social and Cognitive Implications, Too?
Another 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 empathy
vi
. In the journal
Frontiers of Neurology and Neuroscience
vii
, 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."
Yawning has even been associated with arousal
viii
or a change of state, such as going from being alert to sleepy or vice versa, according
to Dr. Robert Provine
ix
, 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
33 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.
References:
i
Yawning and thermoregulation in budgerigars, Melopsittacus undulatus,
Animal Behavior
, January 2009: 77(1); 109-113, Andrew C. Gallup, et al.
ii
See Reference i.
iii
Contagious Yawning and Seasonal Climate,
Frontiers in Evolutionary Neuroscience Variation
, 2011: 3(3); Andrew C. Gallup and Omar Tonsi Eldakar.
iv
The Yawn Explained: It Cools Your Brain,
Discovery News
, December 15, 2008: Jennifer Viegas.
v
Human Paranasal Sinuses and Selective Brain Cooling: A Ventilation System Activated
by Yawning?,
Medical Hypotheses
, December 2011: 77(6); 970-3, A.C. Gallup, G.D. Hack.
vi
Contagious Yawning in Chimpanzees,
Proc. Biol. Sci
., December 2004: 7(271); JR Anderson, et al.
vii
Yawn, Yawn, Yawn, Yawn; Yawn, Yawn, Yawn! The Social, Evolutionary and Neuroscientific
Facets of Contagious Yawning, Frontiers of Neurology and Neuroscience, 2010: 28;
107-12, S.M. Platek.
viii
If Sex Is a Yawn, You may Actually Be Turned On,
MSNBC.com
, July 7, 2009: Brian Alexander.
ix
Robert Provine - Research,
UMBC.edu
.
Source:
Medical Hypothesis December 2011; 77(6):970-3
Post your comment
View Comments (113)
Previous Article
Next Article
Inside Mercola.com: About Dr. Mercola
Articles
Blog
Contact Us
Dr. Mercola's Clinic
En Espanol
Jobs
Podcasts
Press Room
Shopping Cart
Special Reports
Video Library
Wholesale Program
Products: Air Purifier
Bath Care
Cookware
Dental Care
Feminine Care
Krill Oil
Organic India
Power Plate
Probiotics
Productos
Protein Powder
Skin Care
Tanning Beds
Vision Fitness
Water Filters
All Products
Special Info Sites: Aspartame
Cancer
Fitness
Fluoride
Fructose/Sugar
GMO
Mercury
Nutritional Typing
Pets
Vaccines
Vitamin D
*These statements have not been evaluated by the Food and Drug Administration. This
product is not intended to diagnose, treat, cure or prevent any disease. If you are
pregnant, nursing, taking medication, or have a medical condition, consult your physician
before using this product.
Privacy Policy
|
Terms of Use
Disclaimer:
The entire contents of this website are based upon the opinions of Dr. Mercola,
unless otherwise noted. Individual articles are based upon the opinions of the respective
author, who retains copyright as marked. The information on this website is not intended
to replace a one-on-one relationship with a qualified health care professional and
is not intended as medical advice. It is intended as a sharing of knowledge and information
from the research and experience of Dr. Mercola and his community. Dr. Mercola encourages
you to make your own health care decisions based upon your research and in partnership
with a qualified health care professional.
†The World's #1 Natural Health Website claim is based upon
Alexa Natural Health Website rankings
.
If you want to use this article on your site please
click here
. This content may be copied in full, with copyright, contact, creation and information
intact, without specific permission, when used only in a not-for-profit format. If
any other use is desired, permission in writing from Dr. Mercola is required.
© Copyright 1997-2012 Dr. Joseph Mercola. All Rights Reserved.
_______________________________________________
acb-chat mailing list
acb-chat@acb.org
http://www.acb.org/mailman/listinfo/acb-chat
No comments:
Post a Comment