Going Higher: Risk Factors for Acute Mountain Sickness

In a recent post on this blog, we looked at the Canadian Academy of Sport and Exercise Medicine Position Statement:  Athletes at High Altitude.

Turns out, we’re not ready to get out of the mountains quite yet.


3310 meters high in Taiwan: Jiaming Lake

Among the many features of CJSM I have come to appreciate as a reader, a reviewer, an author, and now as an editor is our ‘Published Ahead of Print’  (PAP) section.  Articles that CJSM publishes ahead of print have gone through peer review and been accepted for publication; there may still be some final changes to the paper prior to full print publication.  PAP represents just one of the initiatives we make in keeping with our commitment to getting high-quality, peer-reviewed, clinically relevant publications disseminated as quickly as possible.

One of our most recent PAP offerings comes to you from a group primarily comprised of emergency medicine physicians from Taiwan:  Hsu T, Weng Y, Chiu Y, et al. have published an interesting study on the Rate of Ascent and Acute Mountain Sickness at High Altitude.

The authors share their results from a study conducted during an ascent in Yushan National Park, Taiwan.  In a prospective, non-randomized study design, the authors followed two groups of trekkers up to Jiaming Lake to ascertain whether rate of ascent, as they hypothesized, was related to onset of acute mountain sickness (AMS).  91 young adults chose one of two routes up and down a mountain:  43 chose a ‘fast ascent’ approach (going 8.4 km from 2370m to 3350m in one day) and 48 chose a ‘slow ascent’ approach (covering this distance in two days).  Significantly, given the groups were non-randomized, the authors looked at possible confounders which were not equally distributed among the participants and found statistically significant differences in history of alcohol consumption (more common in ‘fast ascent’–maybe higher rates of risk taking?!) and climbing experience above 3000 m (more common in the fast ascent group).  Otherwise, the groups were well matched by BMI, age, gender, smoking status, etc.

An a posteriori power analysis was done and demonstrated that there was a 5% chance of Type II error given the numbers studied. Read more of this post

High Altitude Medicine

I was thinking about Mt. Everest the other day.


Mount Everest. Photo by Kerem Barut.

No, I will NOT be attempting the mountain myself!  In my youth I had such dreams……the story of Sir Edmund Hilary and Sherpa Tenzing Norgay thrilled and inspired me.

I think one of the defining experiences of middle age is to be certain that some dreams will never be fulfilled; to be content with that realization; and also, to know that there are other dreams, other challenges that can excite.

Yes, I am middle aged!

What got me to thinking about the mountain?  I am sure you have read, there was a terrible accident taking the lives of at least thirteen Sherpas which occurred last week. In reading the reports of that event, I realized that the spring summit period for the mountain had begun:  a narrow window in May  represents a period during which a huge number of ascents are attempted.  For instance, it was May 1996 when the climbing expeditions described by John Krakauer in ‘Into Thin Air’ took place.  This book introduced me to the reality of commercial climbing on the mountain.

If anything, it would seem that ever-greater numbers of people with perhaps limited technical climbing skills are attempting Everest:  an article in today’s New York Times notes that there are 334 expeditions planned for the 2014 climbing season!  This same article also notes in the wake of this most recent climbing disaster involving the Sherpas that this group of expert climbers–so vital to the performance of expeditions on the mountain–is planning a ‘work stoppage.’  I do not know all their demands, but the Times article notes that the stoppage was proposed in the wake of the Nepali government’s offer of a mere $400+ dollars as compensation for the families of the dead climbers.

On a more quotidian front, May represents for us here at CJSM our own challenge:  bringing out the third issue of the journal for 2014!  It’s too soon to say goodbye, however, to the March 2014 issue, and in light of the events on Everest I did want to commend to you an excellent piece in that issue:  The Canadian Academy of Sport and Exercise Medicine Position Statement:  Athletes at High Altitude.

As I’ve said, I, at least, may never make any Himalayan summits….but I fully expect as a sports medicine physician to care for people who succumb to one of the variety of altitude illnesses described in this article.  As the position statement emphasizes, injuries and illnesses associated with high altitude are no longer seen only in mountaineering: athletes, including many from the endurance disciplines, will train at altitude; and many athletes, of all types, will compete at altitude (think Mexico City Olympics, or even coastal Californian on a long-weekend’s ski trip to Aspen).  Staying ‘on top’ of the current thinking regarding this issue would be de rigueur for any of us clinicians caring for athletes. Read more of this post

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