High Altitude Medicine
April 23, 2014 1 Comment
I was thinking about Mt. Everest the other day.
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.
The three main conditions discussed in the paper include Acute Mountain Sickness (AMS), High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE). Here are just some of the pearls I walked away with:
1) Rapid ascent rates are associated with higher risk of developing the above conditions. Acclimatization is important (though not always possible on modern day travel schedules)! To avoid AMS, the pace of ascent is rather slow: above 3000m, one should gain at most 600m/day.
2) Acetazolamide is useful in the prevention of AMS, but should be avoided in athletes who are to be tested as part of anti-doping programs: as a diuretic, it is categorically banned.
3) There is some evidence that Dexamethasone can be used for prevention of HAPE and HACE as well as AMS. As a steroid, it too should be avoided by athletes who must be tested as part of an anti-doping program.
4) Ultraviolet (UV) radiation is not only associated with cancer and cataracts but is a risk factor for immunosuppression. Furthermore, UVA and UVB radiation exposure increases form 11% to 19% with each 1000m gain in elevation
5) ‘Live High Train Low’ (LHTL) strategies were discussed in the statement; these training strategies have been demonstrated to improve performance at sea-level, though I learned the evidence is limited for performance at altitude (> 2000m).
6) Nutritional strategies for coping with and improving performance at altitude include high carbohydrate diets (sorry paleo fans, but a carb diet is associated with increased ventilation rates and higher levels of oxygenation, according to the paper); staying well hydrated; and having a low threshold for iron supplementation.
This list is by no means exhaustive. I recommend it as excellent reading for all clinicians, but most especially those like me who reside at a whopping 275m (Columbus, Ohio) and may be less familiar with these issues on a day-to-day basis.
For readers who want to learn more about the on-going fallout of the recent Everest disaster, I recommned following Ed Marzec’s website.