Re: adjusting to altitude

["Susan Evans Garlinghouse" <suendavid@worldnet.att.net>]

>Cool, I didn't know about horses storing extra RBCs (wouldn't that be
>nice if we humans could do that too!).
>
>Since it's a topic of interest to me (and sounds like to others too),
>would you mind explaining what happens physiologically to the horse over
>the three week period of acclimatizing?  Is it just releasing even more
>RBCs or is there more to it?

Mostly, it's an increased production of certain proteins that support oxygen
transport in the blood.  Erythropoetin, DPG, etc.  The pathways aren't very
well worked out, yet.  So far, Cal Poly is the only university doing much
work on it.  They're mostly trying to figure out why humans get high
altitude sickness and equids don't.  So far, they don't really know.



I'd also be interested in knowing why three
>weeks is optimal and how complete the accimatization actually is.
>Lastly, why is it that horses don't do as well as mules and burros once
>you increase the altitude much beyond about 10,000 to 12,000 feet? Does
>anyone have a contrary experience?

The data they collected included both horses and mules.  I don't think they
know why the differences, yet.  If I remember correctly, acclimitization
continues after the first few weeks, just at a slower rate.  You got the
most response the first week, less the second, less the third, and so on.
No one has collected data long enough to determine exactly how long it takes
for total acclimitization.

Susan G



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