pwn consulting: Digression: Mount Whitney, Age and AMS

Sunday, October 12, 2008

Digression: Mount Whitney, Age and AMS

Sent to you by nigel via Google Reader:

Digression: Mount Whitney, Age and AMS

via Paul Kedrosky's Infectious Greed by pk on 10/12/08

Interesting new research paper in one of my favorite journals (Medicine & Science in Sports & Exercise). Two things caught my eye. First, that the likelihood of developing acute mountain sickness -- an altitude-related disorder that can be life-threatening -- fell with age. I am a frequent high-altitude trekker, and that is news to me. Second, it is fascinating that 41% of the trekkers on Whitney had AMS, and yet 81% of those people still reached the summit. As the quotation goes, In the midst of life we are in death.

Here is the full abstract:

Mt. Whitney: Determinants of Summit Success and Acute Mountain Sickness

Medicine & Science in Sports & Exercise. 40(10):1820-1827, October 2008.
WAGNER, DALE R. 1; D'ZATKO, KIM 2; TATSUGAWA, KEVIN 3; MURRAY, KEN 4; PARKER, DARYL 5; STREEPER, TIM 5; WILLARD, KEVIN 5

Abstract:
Purpose: The aim of this study was to determine the prevalence of summit success and acute mountain sickness (AMS) on Mt. Whitney (4419 m) and to identify variables that contribute to both.

Methods: Hikers (N = 886) attempting the summit were interviewed at the trailhead upon their descent. Questionnaires included demographic and descriptive data, acclimatization and altitude history, and information specific to the ascent. The Lake Louise Self-Assessment Score was used to make a determination about the occurrence of AMS. Logistic regression techniques were used to calculate odds ratios (OR) for AMS and summit success.

Results: Forty-three percent of the sample met the criteria for AMS, and 81% reached the summit. The odds of experiencing AMS were reduced with increases in age (adjusted 10-yr OR = 0.78; P < 0.001), number of hours spent above 3000 m in the 2 wk preceding the ascent (adjusted 24-h OR = 0.71; P < 0.001), and for females (OR = 0.68; P = 0.02). Climbers who had a history of AMS (OR = 1.41; P = 0.02) and those taking analgesics (OR = 2.39; P < 0.001) were more likely to experience AMS. As climber age increased, the odds of reaching the summit decreased (adjusted 10-yr OR = 0.75; P < 0.001). However, increases in the number of hours per week spent training (adjusted 5-h OR = 1.24; P = 0.05), rate of ascent (adjusted 50 m[middle dot]h-1 OR = 1.13; P = 0.04), and previous high-altitude record (adjusted 500 m OR = 1.26; P < 0.001) were all associated with increased odds for summit success.

Conclusions: A high percentage of trekkers reached the summit despite having symptoms of AMS.