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RE: AW: Denver, BEWARE!
Group,
I have no references to offer but I participated in a VERY informal study or
test of the following. Hemoglobin as I understand it does increase at
higher altitude [lower pressure] within limits. I used to back pack and on
one trip above 10K feet somebody brought along a device that measured
hemoglobin content of blood, so many of us poked ourselves and read the
content, before the trip and every few days on it. It takes a few days for
the adjustment to start and I'm not sure how long it takes to be complete.
A search should find explanations of it, this was 35 years or so ago so it
is not exactly knew knowledge. But as I said I do not have a reference just
first hand experience. People with altitude sickness apparently do not make
the adjustment and can not adapt to higher altitudes.
Common advice made by Denverites to out of towners coming to ski, is to
spend the first afternoon or night either in Denver or at the ski resort
enjoying the scenery before hitting the slopes. People who fly in, and go
straight to the slopes are prone to some high altitude adjustment problems,
mostly headaches I believe.
While I have not been following the discussion of cancer incidence I gather
it is supposed to be less except possibly for skin cancer. I believe that
while that may be [or maybe not] true we have a much higher incidence of MS
than the average for the rest of the country.
Please note I am not ascribing the MS incidence to altitude, atmospheric
pressure, radiation, or the Denver parking gestapo, or anything other cause.
Any opinions in this e-mail are solely those of the author, and are not
represented as those of the VA Eastern Colorado HCS, the Dept. of Veterans
Affairs, or the US Government.
Peter G. Vernig, Radiation Safety Officer, VA Eastern Colorado Health Care
System, 1055 Clermont St. Denver, CO 80220, peter.vernig@med.va.gov, Phone=
303.399.8020 x2447; Fax = 303.393.5026, alternate fax, 303.393.5248
"...whatever is true, whatever is noble, whatever is lovely, whatever is
admirable, if anything is found to be excellent or praiseworthy, let your
mind dwell on these things."
Paul of Tarsus
-----Original Message-----
From: owner-radsafe@list.vanderbilt.edu
[mailto:owner-radsafe@list.vanderbilt.edu]On Behalf Of Bradshaw, Keith
Sent: Monday, December 20, 2004 9:40 AM
To: radsafe@list.vanderbilt.edu
Subject: RE: AW: Denver, BEWARE!
>>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
web: www.niras.co.uk
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