[cdt-l] Day hiking at high elevations

[cdt-l@mailman.backcountry.net (Jordan, Ryan)]

Try to spend a night or two at 7k before hiking higher. It will train your
body to adapt to low O2 levels at that elevation. Also, on your first day of
hiking, try to hike up to about 10,000 or 11,000 feet, then return to sleep
at 7k. You should then be in good shape (well, given the time limits of your
holiday, of course) to tackle a 14er with a high degree of success and a low
chance of acute mountain sickness (AMS) or high altitude pulmonary edema
(HAPE).

You will likely experience mild AMS symptoms (headache, nausea, shortness of
breath, dizziness) if you're going above 12k. It's quite common for
sea-level residents to experience AMS above 8k. HAPE symptoms (fluid in
lungs, coughing fluids, wet wheezing) are pretty rare at elevations here in
the lower 48, but they do occur on occasion, just be aware of it. To be
honest, it takes several weeks for your body to truly acclimitize to
elevations greater than 8k, but given the limits of most hiking holidays,
this is unrealistic, and you have to hope for the best. There is a high
chance that your body's physiological ability to use oxygen above 8k will
degrade during your holiday regardless of your acclimitization schedule. It
happens to most people--O2 utilization rates dip for several days and then
slowly become more efficient over a period of 6-8 weeks.

Fluid intake has major consequences at altitude because the air tends to be
drier and you tend to respire more in response to low oxygen availability
(thus losing moisture through respiration) but it probably has little impact
on whether or not you'll experience true AMS (although dehydration can cause
similar symptoms). Predisposition of someone to AMS and HAPE depends
primarily on acclimitization schedule and secondarily on an individual's
physiology. So, take care of the former and hope for the best on the latter.

Good luck and have a great time,
Ryan