Date: Tue, 24 Dec 1996 18:20:10 -0500 (EST)
To: Ultra@caligari.Dartmouth.EDU
From: chiptrnr@mail1.nai.net (Frank R Tuthill)
Subject: acclimatization

Gentlemen and Ladies,

 There have been numerous replies to the question of acclimatization. It is
my opinion that none have adequately addressed the issue.I am not a
Physician  . My personal experience includes ascents of slightly over twenty
thousand feet. I have climbed and trekked over 12,000 feet for a total of
thirty days in the past eight years.  These trips were to Alaska, the
Cascades, Mexico, South America and Nepal. Fortunately, and with proper
precautions, I have only developed AMS, but other members of the parties did
exhibit symptoms of HACE.

 The time proven method of acclimatization is a slow assent allowing the
body time to adapt and recover from  the reduction in partial pressure at
altitude. The climbers adage is "climb high and sleep low" . This allows the
body to recover from the stresses of hiking or running at altitude. Without
the descent back to a lower altitude recovery is either limited or proceeds
very slowly, if at all.  The oxygen content remains the same at 20.96 % but
the mechanisms to transport and utilized oxygen are compromised.  This
pressure gradient is also effected by blood acidity and temperature.
"Pressure breathing" increases the partial pressure resulting in greater
saturation of hemoglobin in the blood. The resulting greater tidal volumes
can aid in performance. There is a caveat. The lowering of blood acidity
from pressure breathing can cause hyperventilation syndrome. This in turn
can cause  faintness, dizziness, cramps and collapse. For the most part , we
cannot aid in the acclimatization process. We can hinder it . Proper fluid
intake is key. It is still more unfortunate that while being fit does help
acclimatization, it in no way guarantees acclimatization. To that I can
personally attest.

Each runner must allow for his or her  body to acclimatize. In my own case (
this is only for me and may or may not be appropriate for others) I will
take 3-5 days and 5-7 days to acclimatize to 10,000 and 14,000 feet
respectively. At arrival to a higher elevation both respiration and heart
rate increase automatically. This occurs for two or three days . It is
normal but can result in difficulties in sleeping. The increase blood flows
felt to me as a drummer in my head. There are a number of conditions not
normal that can occur to persons  at altitude.

AMS

Acute Mountain Sickness afflicts 15-17% of people who ascend to 8,000 feet
or higher too rapidly. Symptoms include headache, shortness of breath,
disturbed sleep and sometimes nausea and vomiting. While  death may seem
preferable , it rarely requires treatment. Onset may begin  slightly after
arrival.

HAPE

High Altitude  Pulmonary Edema generally occurs at elevations greater than
9,000 feet taking 36 to 72 hours to develop. Shortness of breath and bloody
sputum is likely. Headache and great fatigue are common. DEATH  may occur
rapidly.

HACE

High Altitude Cerebral Edema may occur as low as 9,000 feet. Ataxia is a
simple test for possible HACE. Enclose the runner with your arms. An ataxic
runner will  be unable to maintain equilibrium within your arms. Mental
confusion and hallucinations are common. DEATH MAY OCCUR WITHIN FOUR TO SIX
HOURS

Unfortunately these conditions do not occur individually. They may all be
present to varying degrees . They may also progress from one to another with
frightening rapidity.  The aggregate symptoms may mask a clear diagnosis.

These are the only options  where HAPE or HACE are suspected:

descend
                        Descend

                                                DESCEND

Your life may be at stake.

This is not meant to be alarmist, but merely to outline some medical
considerations of high altitude events. While it may seen that arriving at
the last minet will prevent these dangers. I do not believe that correct.
Consider that for every 1,000 feet  above 5,000 feet  the runner will find
his sea level performance reduced by 3%. At Hardrock, we can expect  an
average reduction of 18% . In fact most runners appear to have a much
greater than 22% increase in their times. It may well be that there are no
comparable sea level courses to compare. I plan on arriving two weeks early
to hike the course and see the country. What a great way to acclimatize.

For additional reference I recommend :

Going Higher, by Charles Houston, MD
Little, Brown and Co.  Boston

A very readable volume from which I have borrowed freely,

Merry Christmas to all, and to all a good night,

Chip Tuthill    Chiptrnr@ct1.nai.net