RE: AW: Denver, BEWARE!

["Bradshaw, Keith" <keith.bradshaw@niras.co.uk>]

>>When I'm a mile high, I breathe harder than at sea level, so I naturally 

>>thought that the body makes up for the thinner air by trying to inhale 

>>more of it.



>I hear people say the body makes up for the thinner air by making more red 

>blood cells. (It takes a few days to adapt.) The implication is: we don't 

>inhale a larger volume, but I have never seen any data. I would appreciate 

>a reference to real data, if anyone can provide it.



My theory:

The haemoglobin oxygen saturation stays pretty constant down to about 14%

oxygen, or the equivalent in altitude, then it falls away quickly.  Once you

are in this steeply falling region of the curve, the actual tissue

concentration of oxygen will be significantly reduced.  The haemoglobin acts

as a buffer for oxygen concentration in the tissues.



I think the real issue is the oxygen tension or partial pressure.  I suppose

you could argue any increased number of red blood cells, as a result of

adaptation at altitude, would deliver the same oxygen to the tissues, but

perhaps that only happens when the tissues demand it.  Irrespective of the

actual amount of haemoglobin, the saturation curve is the same shape.



If this is the correct way of looking at it, that means there is

significantly less oxygen-generated free radical damage at altitude.  This

more than makes up for the increased cosmic ray dose, possibly explaining

the longevity of people who live up mountains.



Perhaps we need a proper physiologist to comment !!



Personal views only



keith.bradshaw@niras.co.uk





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