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#51513 - 08/10/17 09:27 AM AMS at 10,000 feet
Steve C Offline


Registered: 09/22/09
Posts: 7235
Loc: Fresno, CA
Here's an AMS story that ended in a helicopter evacuation.

The hiker started at 10,000 feet elevation at Horseshoe Meadows. He felt sick after sleeping overnight there, but proceeded to hike to near Crabtree Meadows. His condition deteriorated to the point he could not walk out.

Here's the story:   A John Muir Trail Thru Hike Derailed

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#51536 - 08/11/17 11:07 AM Re: AMS at 10,000 feet [Re: Steve C]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 989
Loc: Richmond, Virginia
Thanks for posting this Steve

First thought is that sleeping first night above 10,000 ft breaks the rule of intermediate heights before sleeping that high. Sleeping height impacts risk of AMS more than daytime for a physiological reason. Some people cannot tolerate a rapid height advance. Everyone has their own tolerance level getting started as well as ceiling later on.

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#51540 - 08/11/17 01:38 PM Re: AMS at 10,000 feet [Re: Harvey Lankford]
Steve C Offline


Registered: 09/22/09
Posts: 7235
Loc: Fresno, CA
Harvey, maybe this is mostly anecdotal, but for myself, driving directly to 10k elevation and sleeping has worked well for me. And I've been recommending people do that in preparation for their Whitney adventures. I usually take 62.5 mg Diamox in the morning and before that first night, too.

I've only seen a few rare cases, like this one, where people were susceptible to definite AMS problems doing this. It is pretty clear for these few that their "intermediate height" for a first night is somewhere below 10k.

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#51541 - 08/11/17 03:43 PM Re: AMS at 10,000 feet [Re: Steve C]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 989
Loc: Richmond, Virginia
Originally Posted By: Steve C
I've only seen a few rare cases, like this one, where people were susceptible to definite AMS problems doing this. It is pretty clear for these few that their "intermediate height" for a first night is somewhere below 10k.

Steve , we are both correct. Most people get away with it, but a few are very susceptible. Unfortunately there is no good sea level test to predict this, only experience up high. First time, or even subsequent ones , can be hard. If they gave him O2, I wonder if if had more than AMS, but also HAPE.

AMS usually starts to get better once the decision to descend has been made or with only short descent. Generally speaking, HAPE and / or true exhaustion and/ or other illness would take longer.

A bit smokey in Mammoth.

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#51542 - 08/11/17 03:57 PM Re: AMS at 10,000 feet [Re: Harvey Lankford]
+ @ti2d Offline


Registered: 10/22/09
Posts: 805
Loc: Oh Cursed, USA
Originally Posted By: Harvey Lankford
...A bit smokey in Mammoth.


Empire Fire in YNP (750 acres) and Butte Fire (570 acres) in Sierra National Forest perhaps.
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#51545 - 08/11/17 06:20 PM Re: AMS at 10,000 feet [Re: Harvey Lankford]
terraelise Offline


Registered: 06/29/17
Posts: 18
Loc: CA
I'd like to note that you never know when AMS will strike or how hard. I have hiked all over and usually the most I get is a lack of appetite. I have been fairly lucky and altitude is mostly about thin air for me to this point.

The only time I really got questionable symptoms was at lower elevation: hiking SoCal's San Jacinto from the tram. Once, of the three times I have done it, somewhere near switchbacks at 9k I had to sit and rest and eat - a longer break than I typically ever do for any reason. I'm sure it was the extreme of coming from so low up the tram to so high that did it (I also live very low in the OC) - plus... Aunt Flo (sorry guys, but it has to be noted).

I have heard many stories of experienced high elevation hikers suddenly having severe AMS symptoms on a hike but never before or after: fine on Kilimanjaro (19.3k) then sick on San Gorgonio (tops out at 11.5k). Some perfect storm of conditions? I don't know, but I'd warn that just because you haven't had it before doesn't mean you won't. FWIW
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#51549 - 08/11/17 07:13 PM Re: AMS at 10,000 feet [Re: terraelise]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 989
Loc: Richmond, Virginia
Originally Posted By: terraelise
I'd like to note that you never know when AMS will strike or how hard. I have hiked all over and usually the most I get is a lack of appetite.

The only time I really got questionable symptoms was at lower elevation: hiking SoCal's San Jacinto from the tram. Once, of the three times I have done it, somewhere near switchbacks at 9k I had to sit and rest


Yep, 9000 will do it, in fact, current official threshold is 8000 and some talk of 7000 .

Yep again, a lot of unpredictability about who , when, where, other factors


Need more than loss of appetite at high altitude to make a diagnosis of AMS. See Lake Louise Score of AMS

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#51557 - 08/12/17 12:29 PM Re: AMS at 10,000 feet [Re: terraelise]
+ @ti2d Offline


Registered: 10/22/09
Posts: 805
Loc: Oh Cursed, USA
terraelise, I call that area to the summit "Squat Valley" -- where people take a rest along and also mix it in with nature calls. If I remember correctly this area is around 10k elevation. I, too, feel a little woozy at this section when hiking San J. Just a few mountaineer's breaths and I proceed with no adverse effects.

People have difficulty with this and I feel the root cause of this is the Palm Springs Aerial Tramway. The sea level devils from OC and LA have stayed in Palm Springs (elevation 479 feet) at a guest's house or posh hotel. They drive to the Valley Station (2,643 ft. elev., 2,164 elevation change). They hop on PSAT for the 12 minute or so ride (2.5 miles) to the Mountain Station (8,516 feet; 5,873 ft EC).

Over 2.5 miles traveled and 5,873 feet of EC in 12 minutes, to me, may be too much for some people.

I am also curious...could nitrogen be lower as well at higher elevation? Air is 78% nitrogen and 21% oxygen. Decompression sickness (the bends). Altitude and altitude decompression sickness.

Could there be a correlation?

Could nitrogen be the culprit?

Just an observation.
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#51561 - 08/12/17 03:00 PM Re: AMS at 10,000 feet [Re: + @ti2d]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 989
Loc: Richmond, Virginia
The root cause of altitude illnesses is reduction in barometric pressure AND the bodies responses and malresponses to it. The loss of "driving pressure" limits the availability of oxygen. And yes, divers who have been low have rules about when they can fly home because commercial airliners cabin pressure is , guess what,the equivalent of 8000 ft. Too rapid a change in pressure of either O or N can cause various forms of barotrauma


Edited by Harvey Lankford (08/12/17 03:06 PM)

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#51562 - 08/12/17 04:10 PM Re: AMS at 10,000 feet [Re: Harvey Lankford]
+ @ti2d Offline


Registered: 10/22/09
Posts: 805
Loc: Oh Cursed, USA
So, it is not a lack of oxygen or nitrogen, it is the air pressure that makes us sick from the barotrauma. It is starting to make sense. Thank you, Doc!

When an IED explodes, it causes blast-induced barotrauma. If it doesn't kill you, it knocks the wind out of you which is actually the low air pressure after the shock wave passes.

Atomic bomb experiments show the initial blast and shock wave that causes low pressure. When the shock wave dissipates, the surrounding air rushes back in.

So, if you live and train at altitude...I remember the 1968 Olympics in Mexico City. The athletes trained at altitude in Oregon to prepare.

I like this subject.
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#51565 - 08/12/17 06:12 PM Re: AMS at 10,000 feet [Re: + @ti2d]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 989
Loc: Richmond, Virginia
Originally Posted By: + @ti2d

I like this subject.


Me, too. Think about this one: if you are at 40,000 ft and breathing 100% O2 at ambient pressure you will die.

Must have pressure. My use of "barotrauma" was my exaggeration as no one can climb or descend on two feet that fast. A better word for the benefit of pressure is "oxygen cascade" Look up how O2 gets to the mitochondria.

Why die at 40,000 ? Jet pilots wear pressurized masks. Otherwise their entire cabin would need to be pressurized. O2 alone will not work

Resting after a short hike in Mammoth. Acclimatizing

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#51573 - 08/13/17 11:30 AM Re: AMS at 10,000 feet [Re: Harvey Lankford]
wagga Offline


Registered: 10/07/09
Posts: 2213
Loc: Humbug Reach (Pop. 3)
Quote:
I like this subject


ACE gene?
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#51579 - 08/13/17 09:07 PM Re: AMS at 10,000 feet [Re: wagga]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 989
Loc: Richmond, Virginia
Originally Posted By: wagga

ACE gene?

        ACE genotype and Successful Ascent to Extreme High Altitude


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#51582 - 08/13/17 10:28 PM Re: AMS at 10,000 feet [Re: Harvey Lankford]
SoCal Jim Offline


Registered: 06/09/10
Posts: 22
Loc: Santee, CA
Huh. Interesting. Evidence of genetic differentiation related to performance at extreme elevations.

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#51584 - 08/14/17 03:03 AM Re: AMS at 10,000 feet [Re: SoCal Jim]
Marcus Offline


Registered: 07/07/17
Posts: 46
Loc: California
Me and some buddies attempted to hike up to Whitney Peak a couple of weeks back - one of us got AMS symptoms just before Consultation Lake.

We ended up camping at "Consolation Lake" and heading back down the following morning.

What possibly made it worse was that we had visited Bad Water and Death Valley a couple of days previous to the hike up Whitney.

So we effectively went from the lowest point in the USA to the highest - that probably didn't help! grin

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#51587 - 08/14/17 07:59 AM Re: AMS at 10,000 feet [Re: Harvey Lankford]
+ @ti2d Offline


Registered: 10/22/09
Posts: 805
Loc: Oh Cursed, USA
Originally Posted By: Harvey Lankford
Originally Posted By: wagga

ACE gene?


https://www.ncbi.nlm.nih.gov/pubmed/18081503 ACE



Let me guess...

New gene therapy that will replace Diamox in injectable form.

Disclaimer: Avoid prolong use or hyperactivity. May cause swelling of the extremities. Frequent urination or excessive bowel movements may occur. WAG bag sold separately. Available at your local drug store. Consult with your doctor before taking.

Dr. Lankford: In English please for those who may not speak the lingo...
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#51610 - 08/14/17 04:29 PM Re: AMS at 10,000 feet [Re: + @ti2d]
Harvey Lankford Offline


Registered: 11/10/09
Posts: 989
Loc: Richmond, Virginia
Originally Posted By: + @ti2d


Dr. Lankford: In English please for those who may not speak the lingo...


Ha! That is easy.

We are not all alike!

Said another way, if you are of purebred , many centuries genetically adapted Tibetan heritage, then some of you have a metabolic advantage over the rest of us slugs

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#51621 - 08/15/17 07:55 AM Re: AMS at 10,000 feet [Re: Harvey Lankford]
+ @ti2d Offline


Registered: 10/22/09
Posts: 805
Loc: Oh Cursed, USA
Ah, much better...I confess, it was me who couldn't decipher the study.

So, some of us have an ACE up our sleeves?

Why I never...

Won't play poker with them folks...

Genetic cheaters... grin
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#51625 - 08/15/17 09:26 AM Re: AMS at 10,000 feet [Re: Harvey Lankford]
Steve C Offline


Registered: 09/22/09
Posts: 7235
Loc: Fresno, CA
Originally Posted By: Harvey Lankford
We are not all alike!

Said another way, if you are of purebred , many centuries genetically adapted Tibetan heritage, then some of you have a metabolic advantage over the rest of us slugs

Not just Tibetans:   "...and has a greater than normal frequency among elite endurance athletes..."

Endurance athletes may rise to their level of higher output more easily, because they too carry this particular genetic setup.

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#51627 - 08/15/17 09:57 AM Re: AMS at 10,000 feet [Re: Steve C]
+ @ti2d Offline


Registered: 10/22/09
Posts: 805
Loc: Oh Cursed, USA
That's you, Steve, aka endurance athlete!
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