Excessive yawning (1-4 yawns/minute) is associated with a variety of conditions. The majority of these are disorders of the central nervous system, and include epilepsy, encephalitis, brain tumors, multiple sclerosis and progressive supranuclear palsy. Excessive yawning is also associated with opiate withdrawl and the consumption of a variety of drugs that affect neurotransmitters, such as drugs prescribed for Parkinson's disease or depression.
jimmylegs wrote:bummer matt - what kind of mag and how much daily? i never had the yawning prob, just plain old shortness of breath was what the mag fixed for me...
The researchers also looked for a relationship between breathing and yawning by having people exercise. Exercise, obviously, causes people to breathe faster. However, the number of yawns during exercise was not different from the number of yawns before or after exercise. Therefore, it appears that yawning is not due to CO2/O2 levels in the blood and that yawning and breathing are controlled by different mechanisms.
So, the question remains - why do we yawn? Dr. Provine suggests that perhaps yawning is like stretching. Yawning and stretching increase blood pressure and heart rate and also flex muscles and joints. Evidence that yawning and stretching may be related comes from the observation that if you try to stifle or prevent a yawn by clenching your jaws shut, the yawn is somewhat "unsatisfying." For some reason, the stretching of jaw and face muscles is necessary for a good yawn.
In 2007, researchers proposed that yawning is used to cool the brain. They found that people yawned more often they pressed a warm or room temperature towel against their heads than when they pressed a cold towel against their heads. People who breathed through their noses (thought to reduce brain temperature) did not yawn at all.
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