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


Medicine & Science in Sports & Exercise: October 2008 - Volume 40 - Issue 10 - pp 1820-1827
doi: 10.1249/MSS.0b013e31817e91b8
APPLIED SCIENCES: Physical Fitness and Performance

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·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.

1Department of Health, Physical Education, and Recreation, Utah State University, Logan, UT; 2Department of Psychology, Utah State University, Logan, UT; 3Recreation Administration and Leisure Studies Program, California State University, Fresno, CA; 4Department of Family Medicine, University of Southern California, Los Angeles, CA; and 5Department of Kinesiology and Health Science, California State University, Sacramento, CA

Address for correspondence: Dale R. Wagner, Ph.D., Utah State University, 7000 Old Main Hill, Logan, UT 84322; E-mail:

Submitted for publication October 2007.

Accepted for publication April 2008.

©2008The American College of Sports Medicine