Top Menu

Altitude Sickness: John Muir Trail Case Study

Mono Pass

Imagine hiking over Mono Pass then south bound on the John Muir Trail.  Another beautiful week in the Sierra’s with some of your buddies, one who is on his first backpack trip and is blown away by the beauty.  You never had any issues in the Sierra’s except an occasional headache that you could not figure out if due to lack/low amounts of caffeine or to elevation.

Now in 2013 you are hiking the second day and especially the third day and your hiking partner is commenting that this year he can keep up with you and even get in front of you which never happened before.  You are struggling and working hard for hikes that you have never had problems with.

Like a lot of adult males your blaming the extra pounds you put on each year, now up to 215lbs for 5’10” and maybe your age 57 y/o is causing issues.  I swear I’m going to lose this weight when I get back from this hike.  One of the three of us has asthma and he has a dry cough each morning then you also have the dry cough that sounds exactly like his.

While approaching Muir Pass we camped at Wanda Lake at 11,413 ft. elevation.  You were really tired and beat. We had a hail storm for about an hour then you ate a little dinner and lay down to go to bed.  You could not breathe thru your nose because you were huffing and puffing so hard it took 1-2 hours before your breathing to slow down enough that you could fall asleep.

Muir Pass

During the night you awoke with a start because you felt like you were suffocating. This same suffocating thing happened once at Philmont three weeks previously but the MDs in the Philmont Health Lodge could not figure it out.  You were very anxious and got out of your tent and sit on a large rock and watch meteors go by.

You tried lying down again but your anxiety was so high it felt like you were not getting air and were breathing hard so you re-staked your tent so more air could flow thru it since you had it staked tight to the ground due to the hale storm.  It did not help so you pulled my ground cloth, pad, & sleeping bag outside the tent and eventually fell asleep.  This whole time you did not wake your buddies to give them a heads up that something was going on (not very smart i.e. dumb!!).

So what was going on?

What would you do if you were hiking with me?

My hiking buddies did not have advance wilderness first aid training, just me, and I kept thinking I was getting asthma since I had dry non-productive cough and out of breath.

A 57 y/o, overweight, high blood pressure controlled on medications one being a diuretic (water pill), lives at sea level, spent one night at Mammoth condo (7800 ft.) before climbing Mono Pass (12,000 ft.), had dinner and a few beers with his buddies before going to bed in Mammoth.  Does this sound like a few people in the mountains?

Do you just say to yourself we’ll see how he is doing in the morning before you go to bed?

What I had is the most common cause of DEATH in the mountains.

The rest of the hike was extremely hard but I did feel better at low elevations but we went over Muir Pass then to camp at Dusy Basin (10,742 ft.) then out the next day over Bishop Pass (12,000 ft.).  I made it, but I was totally exhausted for a hike I should have had no problem with.  I drove home the next day after spending the night at a Mammoth condo.

Mount Whitney

HAPE – High Altitude Pulmonary Edema

I actually had two things going on; the first and more important was HAPE – High Altitude Pulmonary Edema which is the most common cause of death at elevation; the second thing going on was Periodic Breathing, something I never heard about and the MDs at the Philmont Health Lodge knew nothing about.

HAPE I always thought had blood tinged sputum that you were coughing up.  Since I had a non-productive cough, I did not even think of HAPE.

A cough plus weakness/decreased exercise performance should set off some warning bells that should cause you to think of HAPE.

The main signs of HAPE are:

  • trouble breathing – first with exercise, then even at rest.

  • tired and weary with weakness

  • coughing – first with exertion, then at rest

  • frothy and later blood in spit

  • lips, tongue, nails become blue.

Atypical HAPE: 5-10% of HAPE cases

  • No respiratory symptoms, no breathing issues.

  • Just get weak, quiet, blue, then dies.

  • Need pulse oximeter to diagnose (section on this later)

Progression of HAPE is accelerated by cold exposure, vigorous exertion and continued ascent.

HAPE can develop in 1-2 hours or over several days and even when descending.  I had a bunch of these symptoms.

Untreated HAPE can have a mortality rate of up to 50%.

I attended a conference in October 2013 (American Mountain Guides Association: Advanced Mountain Medicine for Guides, The Lhotka Conference) which had two of the world’s experts on altitude illnesses, Peter Hackett, M.D. & Peter Bartsch, M.D.  The presentations and reference articles from the conference.

First rule of thumb they emphasized if anything “strange” is going on (medically) when at elevation, it is related to the elevation until proven otherwise. The second rule of thumb is to get the person down to an elevation when the “strange” thing was NOT going on if possible and as quickly as possible.

HAPE: What to check for:

  • Has there been a recent ascent?

    • HAPE usually develops 2 or more days after ascent to 10,000+ feet elevation and is rare at elevations less than 10,000 feet.

  • Does it take a long time to get breath back after exercise?

  • Are they breathless when resting?

  • Is the breathing rate increased?

  • Can a “wet” crackle sound be heard in the chest? Put ear to back below shoulder blades?

  • Has the oxygen saturation decreased further than the hiking group if carrying pulse oximeter?

  • Has the heart rate increased further than the hiking group?

  • Is there a past history of HAPE?

Risk factors for developing HAPE:

  • Previous history of HAPE

  • No pre-acclimatization

  • Fast rate of ascent

  • Hard exertion

  • Living at altitude less than 1500 feet

  • Obesity (BMI>30)

  • Acute or Chronic lung disease

South John Muir Trail

Never leave a sick person alone.  There were a number of stories of treks leaving someone behind to rest because they could not keep up, with plans to pick them up on the way back later in the day. When they returned they found them dead.

Something I learned at the conference is that two types of people tend to get themselves into trouble with HAPE and other altitude illnesses (HACE-High Altitude Cerebral Edema, AMS-Acute Mountain Sickness) because they do not communicate well with the group.

The first is the quiet person that says nothing to anyone that will climb into their tent when not feeling well.  The second problem person is the highly trained athlete because they are used to working thru the pain and are embarrassed about admitting they are having problems.  They both tend to minimize issues/deal with them quietly or not even admit to having issues.  They may be critical or not even alive come morning.

The main treatment available to us is to DESCEND NOW, not later or in the morning.

Lighten or remove their pack and get them quickly down in elevation.  Do not lay them down but have them sit up while keeping them as warm as possible if resting or sleeping.  Sitting up will allow them to breath a bit better.   Other options are available for larger expeditions such as oxygen if carrying oxygen tanks or hyperbaric pressure bags but most of us hiking in the U.S. will not have these options available.

There are medications you can take if you brought them along with you (see medication table), but you still will need to DESCEND IMMEDIATELY. Descend to as low an elevation as possible.

Someone in the group needs to take responsibility to question and check on all members of the group each day or multiple times each day.  The consequences if symptoms are ignored, are breathing stops!  DEATH!  In very serious cases death can occur within as little as an hour of symptoms being noticed.

Periodic Breathing

Also called Cheyne Stokes breathing occurs at night when rapid breathing is followed by periods when breathing briefly stops.  This is common at elevations over 9,000 feet and almost everyone gets it at 16,000 or greater.  Often you will not get very restful sleep and sometimes you will wake during the night from sleeping feeling like you are suffocating.  Waking like this is a bit scary, my adrenaline was very high the two times I woke up from this both times when sleeping above 10,000 feet.  This may get better with acclimatization.  A good reference is: Sleep at Altitude addresses a number of altitude illnesses plus some Cautionary Tales from the mountains or other sites are Pulse Oximetry at High Altitude and from this site High Altitude Symposium.

Pulse Oximetry

Peter Hackett, M.D. & Peter Bartsch, M.D. highly recommended and discussed using very small (light) finger-tip pulse oximeters to monitor the oxygen saturation and pulses in each member of your group.  If one person’s oxygen saturation has decreased further than the groups this may be indicative of HAPE starting especially when combined with other physical symptoms of HAPE we discussed above.  Measure the saturations at similar times and circumstances such at dinner after everyone has sat and rested for a while.  Be very careful of telling everyone their oxygen saturations because it tends to be a game in a group trying to get the best oxygen saturation numbers.  This is needed to diagnose atypical HAPE that really has no symptoms other than drop of pulse oximetry.  See the document “Protocol for use of pulse oximetry (SpO2) when guiding at high altitude” at High Altitude Symposium for specific recommendations around pulse oximetry.


I will refer you to the really good references that I have included the links which contain recommendations for specific medicines to bring and what doses to take & when.

Guidelines for Field Treatment

Travel at Altitude

Prevention and Treatment


American Mountain Guides Association: Advanced Mountain Medicine for Guides, The Lhotka Conference web site with links to multiple articles & slides from conference.

High Altitude Symposium

Short References:

Travel at High Altitude Booklet

Short Guidelines for Field Treatment


This post was contributed by Trail Ambassador Doug Prosser

, , ,

16 Responses to Altitude Sickness: John Muir Trail Case Study

  1. Daryn August 13, 2014 at 10:41 pm #

    Nice reminder. Thank you. HACE and HAPE are real hazards and don’t only happen in the “death zone.”

  2. Joe C August 15, 2014 at 7:56 am #

    Interesting read. I got AMS for the first time in my life a few years ago; went from 3,000′ to 11,000′ in a day. Doctor had just lowered my BP medicine. Up all night trying to throw up, felt like a super hangover the next morning. Went back down the next day, slept 12 hours. Got up to eat, food sounded horrible, slept 8 more. Felt OK and went back up the next. Scary though; glad I turned around.

  3. C Moore August 15, 2014 at 8:14 am #

    Great job publicizing this issue. I have a collection of news clips of Search and Rescue (SAR) incidents for a couple of years. AMS can contribute to disorientation and getting lost, falling and getting injured, etc. And as a member of American Alpine Club you will get rescue insurance to cover $5K or SAR costs. Best not to become a statistic!

  4. Peter August 15, 2014 at 8:39 am #

    The first mountain I ever climbed was a 14er in Colorado. No acclimatization, no experience, and no concept of how to pace myself. Definitely had a lot of that going on, and was very glad to get back down to a more reasonable altitude (which, surprisingly was still over 10,000 feet) to recuperate. i missed the peak of the mountain by about 30 feet, because I was too dizzy to do a 10 foot vertical climb.

  5. Liz August 15, 2014 at 10:38 pm #

    This same discussion came up recently on a Philmont list. One of our members is an MD/Ph.D.; he stated that recent research is implicating genetics in predisposition to HACE/HAPE/AMS.

  6. renegadepilgrim August 16, 2014 at 7:58 am #

    This is so helpful! I’m heading to Nepal soon and AMS/HAPE/HACE has been at the front of my mind.

    • Doug Prosser August 17, 2014 at 10:11 pm #

      Read through the articles & presentation slides before going. You may want to discuss what meds to bring with Mountain Physician.

      • renegadepilgrim August 18, 2014 at 10:17 am #

        I have read through the articles and links and presentation slides. I used to work with an MD who is a Medical Advisor for Portland Mountain Rescue (who has advised me to take Diamox as well), and also have 14 years experience in Emergency Medicine as an ED Tech. Trust me, I’m doing my research, and in my case, too much knowledge can be a bad thing. :)

  7. Randall Dee August 16, 2014 at 8:56 am #

    Thanks so much for posting this. I’ve done 2 trips into the Wind River Range recently above 10K ft where I kept waking up at night with the feeling that I was suffocating and my breathing had stopped. I live at below 500 ft elevation. If it appears that I have a predisposition to HAPE/HACE, then should I not do these high elevation trips?

    • Rich Jackson August 17, 2014 at 7:47 pm #

      Taking Diamox 250 mg twice a day beginning the day before ascent can help to prevent altitude sickness in susceptible individuals. It is a carbonic anhydrase inhibitor and a diuretic which will also help you sleep at night.

    • Doug Prosser August 17, 2014 at 10:19 pm #

      You may not be experiencing HAPE but Periodic Breathing. Peter Hackett MD said just a little acetazolamide (Diamox) 62.5mg (1/4 of 250mg tablet) prior to bedtime really works to improve sleeping at altitude. I was just at a Wilderness Medicine conference and they called the Diamox a “High Altitude Sleeper Agent” and recommended the same dosage.

  8. kennym101Kenny Meyer October 21, 2014 at 9:45 am #

    Excellent write up. Very helpful. Wish I stumbled into it earlier. Ends up I collaborated with a couple Docs on a similar write up but for JMT hikers.
    Thanks again for writing this up. Regards, Kenny

  9. Karen Najarian November 3, 2014 at 12:03 pm #

    Good read. I have sleep apnea which makes it all worse. As for attributing problems to altitude unless known otherwise, I had one client who’s scalp started itching. Knowing I was supposed to attribute it to altitude but also knowing that didn’t sound right, I missed an allergic reaction he was having to another client’s granola which increased a few days later to anaphylaxis. I did have the good sense to give him a Benedryl the first time around and luckily we were down in Yosemite Valley when the anaphylaxis hit. THEN, I had another gal who was exhibiting altitude symptoms but after an evac it was discovered she was having a heart attack. Doh! Needless to say, REI and I had safety and pre-qualifying disagreements.

  10. deserthiker June 11, 2015 at 11:25 am #

    What the article forgot to mention is the HAPE is rare at elevations found in the Continental US and typically only hits those with a predisposition for it. While the article states that it accounts for 50% of the deaths in the mountains, it doesn’t mean OUR mountains.

    • Doug Prosser June 14, 2015 at 7:58 pm #

      The conference I went to in Boulder had as number of phycians from the telluride ski area that talked about seeing numerous HAPE patients both adult and pediatric. If I recall what they said Telluride has a part of their resort high on the mountain and that is where the patients are coming from.

    • kennym101 June 15, 2015 at 3:46 pm #

      HIgh desert hiker. Just wondering if there what research or reference you found that says HAPE is rare in the Continental US. I’ve been reading that HAPE can occur as low 8K (Gallagher & Hackett, “High-altitude illness.” Emerg Med Clin N Am 22 (2004) 329–355). The average elevation of the JMT south of Donahue pass is 10K. So it would seem that HAPE is a real possibility in the Sierras. Since rescue opportunities in the Sierras is probably much better than they are on South Pole, perhaps you just mean HAPE fatalities? Also, is there a reason you excluded HACE?

Leave a Reply