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#38547 - 07/11/14 06:52 AM Altitude Acclimatization one more time
Bob West Offline


Registered: 11/13/09
Posts: 800
Loc: Bishop, CA, USA
As hikers prepare for their Mt. Whitney trips, we see questions regarding acclimatization to altitude. The following links are to scientific studies on that topic from civilian and military sources. Some of it is very technical, while others are a little more readable. What are they saying in general terms?

In brief, science shows that short-term efforts at acclimatization show little benefit; it is longer term, gradual ascents that display the most benefit. Quick climbs enroute to Mt. Whitney or staying one or two nights at Whitney Portal do not produce the same benefit as staying a altitude for a week or longer at altitude. Acclimatization takes time, anecdotal testimonies to the contrary.

When I lived in the SF Bay Area, it was our typical weekend plan to drive over to the east side on Friday night, get up early on Saturday morning, hike to an 11,000 or 12,000 base camp, bag the peak on Sunday morning, hike out to the trailhead Sunday afternoon, and drive back home late Sunday night. Sound familiar to anyone?

We knew full well the price we might pay for failing to acclimate properly, but we took our lumps without whining too much. LOL.

Hopefully, this information will answer questions regarding acclimatization.

http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-2-the-pre-travel-consultation/altitude-illness

http://www.usariem.army.mil/assets/docs/publications/articles/2004/altitudeacclimatizationguide.pdf

http://hprc-online.org/environment/altitude/short-duration-altitude-acclimatization

http://www.bsa344.com/Guide%20to%20High%20Altitude%20Acclimatization.pdf

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#38550 - 07/11/14 08:22 AM Re: Altitude Acclimatization one more time [Re: Bob West]
Expeditiondan Offline


Registered: 03/24/14
Posts: 17
Loc: California
Thanks for throwing together the articles Bob. It would be good to get these on the sidebar or something for easy reference.

One thing that people also need to keep in mind with any type of clinical research is that each individual will respond differently when exposed to something; in this case high altitude.

While its certainly true that long term acclimation will produce the best results it is also clear that in the short term some acclimation can also stave off the major effects of AMS etc. Of course, you will still be panting up a storm and performing much below your normal athletic level, but at least you may not have severe headaches or nausea.

Then again, I think many people here will attest that their body reacts differently to altitude at different times which is also situation dependent. Sometimes you feel great, sometimes you don't.

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#38551 - 07/11/14 08:43 AM Re: Altitude Acclimatization one more time [Re: Expeditiondan]
Steve C Offline


Registered: 09/22/09
Posts: 7338
Loc: Fresno, CA
Thanks, Bob. I need to check the articles, but do any of them address the short-term symptoms of nausea and headache that plagues so many Whitney hikers? Anecdotal reports support shorter term (2 days/nights at altitude) being helpful in staving off the worst symptoms, which is what Whitney hikers need to do.

> and drive back home late Sunday night.
Oh yeah. Road Warriors and Weekend Warriors. I have always been good with that. Some people are really tired and need to sleep, but for me most of the time, the body is tired but the brain is really stimulated from the just completed adventure.

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#38553 - 07/11/14 10:50 AM Re: Altitude Acclimatization one more time [Re: Steve C]
wbtravis Offline


Registered: 09/22/09
Posts: 1239
Loc: Corner of Jack Benny and Roche...
Bob,

I have felt for the longest time having experience at an elevation is more important than short term acclimatization.

This is why I am big on noobs going to White Mountain or Mt. Langley, once snow clears of the New Army Pass, prior to coming to Mt. Whitney.

I do not have problems going to 14,000' after not being at the elevation for a couple of years because I know what to expect and how to adjust my pace, etc.

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#38557 - 07/11/14 12:46 PM Re: Altitude Acclimatization one more time [Re: wbtravis]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 997
Loc: Richmond, Virginia
ExpeditionDan is absolutely correct.

It depends on what your definition of acclimatization is is.

Can you climb early on huffing and puffing not at your full athletic acclimatization and not suffer classic AMS symptoms like headache, nausea, etc. . Yes. Plenty of people do just that on Whitney with only one or two nights spent high first. Probably half. If they went back there after a week or two longer at elevation, they would find that they breathe easier, climb faster, and don't feel like they are pushing as hard.

The other half suffer BOTH the AMS symptoms and the aforementioned 'Mountaineers Foot."

Anyone who replies please do not get bogged down in statistics but rather the difference in physical presentations. Even the official definitions are not clear

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#38583 - 07/11/14 11:57 PM Re: Altitude Acclimatization one more time [Re: Harvey Lankford]
saltydog Offline


Registered: 02/03/11
Posts: 1552
Loc: Valley Ford CA!!!!
Originally Posted By: Harvey Lankford
ExpeditionDan is absolutely correct.

It depends on what your definition of acclimatization is is.

Can you climb early on huffing and puffing not at your full athletic acclimatization and not suffer classic AMS symptoms like headache, nausea, etc. . Yes. Plenty of people do just that on Whitney with only one or two nights spent high first. Probably half. If they went back there after a week or two longer at elevation, they would find that they breathe easier, climb faster, and don't feel like they are pushing as hard.

The other half suffer BOTH the AMS symptoms and the aforementioned 'Mountaineers Foot."

Anyone who replies please do not get bogged down in statistics but rather the difference in physical presentations. Even the official definitions are not clear


Glad to see Harvey making this point. I have commented before about the dual function of acclimatization: staving off the worst symptoms, vs full (or even significant) athletic acclimatization. I think it is too often overlooked. I have not been able to find out whether Diamox, for example, has been found to help with the latter, but my subjective impression is that it help me a lot last year on the JMT. Felt rapid improvement and athletically acclimated after four trail days, coming from sea level to Yosemite Valley and starting the trail the next day. 5000, 9000 8500 and 9500' respectively the first four nights out of YV. Knocked my hydration all to hell for that period and two more days after, but that was probably due to wrong dosage(4x!) by my doc, and my not checking it till day 2.
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#38585 - 07/12/14 10:31 AM Re: Altitude Acclimatization one more time [Re: saltydog]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 997
Loc: Richmond, Virginia
SD

until I can get back to an ergonomically more useful device........

Acetozolamide (AZ) or Diamox has 3 main benefits to high altitude (HA)

It is a central (brain) respiratory stimulant and helps periodic breathing . This breathing pattern persists even after full acclimatization. Because of that, some would consider it a direct effect of HA independent of AMS. There may end up being some change in the definitions of HA

Secondly, it improves AMS and speeds acclimatization to some degree in only some people only some of the time. It is not a slamdunk

An obscure benefit of AZ but not other drugs in its class is it's ability to reduce the HPV of HA. Hypoxia pulmonary vasoconstriction or high blood pressure in the lungs on exposure to hypoxia either in hypobaric chamber or HA puts a strain on the right ventricle (RV) of the heart. This can occur in hours but usually days or weeks at HA. How much can AZ help this is not entirely clear but is relatively small . Anyone with involvement of the RV is in big trouble and must descend. Same for HAPE that is an entirely different complication involving the lungs and RV.

Also , WADA lists AZ as a PED ( performance enhancing drug) although it really only was based on the second reason I mentioned. HA was a controversial subject at the Mexico City Olympics

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