[pct-l] elevation sickness

[rbelshee at hotmail.com (Rod Belshee)]

I hiked in the Himalayas in 2003 (www.trailjournals.com/annapurnacircuit ) 
and
attended an excellent seminar on AMS in Manang, Nepal. Here's the basics
from that seminar, followed by more detail.

Only a few decades ago, about 10% of mountain trekers in Nepal died from
AMS(!), but that has declined to near zero now. Acute Mountain Sickness
(AMS, or elevation sickness) is now easily avoided with a bit of knowledge.

First, here's the most important rules:
-- gain elevation slowly, 1000 feet per day
-- hike high, sleep low
-- stop gaining at the first signs of AMS, drop elevation if signs remain
(headache, tiredness, dizzy, nausea, out of breath)
-- descend immediately if severe signs occur (pounding headache, unable to
walk a straight line, unable to regain breath, coughing fluids...)
-- avoid the temptation to "not hold up the group" and keep going
-- medications as prophylactics are very controversial
-- watch for both dehydration and AMS, as they are intertwined

Elevations in Nepal are considerably higher than anything encountered on the
PCT. We crossed Thoroung La Pass at 17,500 feet, and looked upward to the
mountains from there! At 14,491 Mt Whitney is much less of a concern. For
most PCT through hikers the natural profile climbing up from Kenedy Meadows
takes care of you automatically, with little special planning. I describe a
typical PCT hiking profile at the end of this message.

Here's more detail on each of the main AMS points:

Gain elevation slowly
-- begin limiting gain and monitoring for AMS at about 9000 feet
-- while a few people experience symptoms lower than that, 9000 feet is
generally conservative
-- gain about 1000 feet a day (some other sources say 1500 feet per day)
-- every fourth day, take a break with no elevation gain
-- do not assume that your are immune if you have not had AMS in previous
climbs

Hike high, sleep low
-- the 1000 foot daily limit applies to sleeping elevation
-- It is good to hike even several thousand feet higher during the day and
descend for sleep
-- Until you are acclimated, plan your hike profile and camp sites
accordingly

Signs of AMS
-- AMS is pressure-endused endema of the lungs or brain
-- The warning signs are related to the brain and the lungs
-- Brain (early signs):  headache, loss of appetite, tiredness, weak, dizzy,
nausea, difficulty sleeping, ...
-- Lungs (early signs):  out of breath after just a few steps, ...
-- Brain (final signs): severe pounding headache, vomiting, cannot walk a
straight line, double vision, changes in behavior, ...
-- Lungs: (final signs): coughing (especially blood), out of breath even
after you stop, ...

Stop or descend
-- at first early signs, stop and observe the symptoms, and drink lots of
water
-- if they worsen at all, descend immediately
-- if they do not clear in a few hours, descend
-- descend until symptoms begin to abate, which often happens in just
500-1000 feet
-- typically it is recommended to descend to the elevation of the prior
nights sleep or lower
-- rest 1-3 days, drinking lots of water, before resuming the climb
-- if symptoms are severe, then death may occur within hours, so descend
completely and get to a hospital

Groups and denial
-- using the 1000 feet per day profile, only 10% of people will have
symptoms
-- in groups, simple arithmetic dictates a higher chance that at least one
member will have symptoms
-- in groups, no one want to slow others down, so the pressure is high to
keep pushing
-- a group of four people has a 41% chance of someone developing symptoms
-- a group of six is more likely to have at least one person develop
symptoms than not!

Medications
-- Diamox is sold to prevent AMS, but prophylatic use is very controversial
and not recommended
-- Diamox speeds up the respriatory system which can mask early symptoms
resulting in a more severe case of AMS
-- Diamox is very useful to for symptomatic relief after onset and during
descent
-- Diamox can never substitute for descent, which is the only cure

Dehydration
-- Drinking lots of water before and during the hike seems to reduce the
likelihood of AMS onset
-- Drinking lots of water is recommended for rest days after AMS onset
-- Symptoms of dehydration and AMS overlap, so always treat for dehydration
when AMS is suspected

PCT climbing profile

A typical northbound PCT hike first reaches 9000 feet in the Sierras at the 
Olancha
Pass Trail cutoff (67.5 miles into section G). Camp in this area, or push
over the 10,500 saddle (71.1) to camp back down at 9000 feet near the
creek before Gomez Meadows (74.8) or at Death Canyon creek (77.2). Either
way the next day crest at 10,700 before descending to camp around 10,000
feet near one of the two springs (82.4, 84.0), or Dutch Meadow (88.9), or
hike out to Trail Pass campground (91.2). You have now hiked high and slept
low, and gained 1000 feet per day. You are now acclimated to camp the next
night at 11,000 which virtually opens up the whole section.

I don't know of anyone who hiked from Kennedy Meadows and developed AMS, but
it in 2004 one hiker hitchhiked from Kennedy Meadows (6000 feet) to
Horseshow Meadows to climb directly up to Trail Pass 10,500, and developed
serious AMS.

Whitney
Before the Mt Whitney ascent, most hikers camp near Crabtree Ranger Station
(10,640) but some hike up to Guitar Lake (11,480) to make it even easier. A
few other 2004 hikers spent the night on Whitney to watch the sunrise, which
exceeds these guidelines and was cold, but they loved it! Remember, these
are just guidelines! They will generally keep you safe with minimal
knowledge about AMS. If you chose to overnight on Whitney, memorize the AMS
signs to watch for, pair up with another hiker or two, be ready and willing
to descend in the dark if necessary, and then sit back and enjoy the
sunrise!

And as a final cross-cultural message, another AMS tidbit from the Nepalese 
guides: eat
garlic soup the morning of your highest climb.

Steady (Sr)


-----Original Message-----
From: pct-l-bounces@mailman.backcountry.net
[mailto:pct-l-bounces@mailman.backcountry.net] On Behalf Of Dustin Prickett
Sent: Saturday, March 19, 2005 9:17 AM
To: pct-l@mailman.backcountry.net
Subject: [pct-l] elevatoin sickness

Elevation sickness, is it a factor for someone who is not used to it and
goes straight up to Whitney?  What is the best way to prevent it, what are
some early the symptoms?  Dustin

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