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Name: Amy
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Question:
Why is it hard to breathe in thin air? What health dangers do mountain climbers face at high altitudes?



Replies:
Among the obvious dangers of losing ones footing, the oxygen available in the air is considerable less at higher altitudes. If I recall correctly, 21% of the atmosphere at standard temperature and pressure at sea level is composed of oxygen. This is less at higher altitudes. One can lose consciousness and even die in an oxygen deficient environment with changes from oxygen content to lower than 19.5%. This can unfortunate effect can occur within minutes.

Dr. Myron


The air is not really thin at high altitudes. The problem is that air pressure is lower. As altitude increases, air pressure decreases. In order for your lungs to fill with air, the air pressure in your lungs has to be less than the pressure of the air outside your lungs. Air moves from areas of higher pressure to lower pressure. As your diaphragm (the muscle that separates your chest cavity from your abdominal cavity) moves downward, the size of your chest cavity increases. This decreases the pressure in your chest and air flows in. When the diaphragm is up, it puts pressure on the chest cavity and the pressure in the lungs is greater than outside the lungs. Air flows out. This is an example of Boyle's Law. The movement of the diaphragm is controlled by the brainstem. Anyway-the reason that it is harder for some people to breathe at higher altitudes is that the air pressure differences aren't as great between the inside of the lungs and outside.

Van Hoeck



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