To the Editor
Mount Aconcagua, at 6962 m, is the tallest mountain in the southern hemisphere and one of the highly sought after 7 summits. It is a preferred destination among climbers owing to the psychological and physical demands it imposes, and serves as a nontechnical introduction to extremely high altitude climbing. With more than 3000 visitors annually attempting the climb predictors of summit success are in demand.
In a 2010 Wilderness & Environmental Medicine article, Lazio et al 1 proposed the use of a 6-minute walk test (6MWT) as a possible predictor of summit success. They found age and post-6MWT oxygen saturations above 75% to be statistically significant predictors of summit success, and suggested the test was easy to replicate in remote high altitude environments.
On an Aconcagua expedition in January 2012, our group of 4 climbers decided to test the reliability of the 6MWT as a predictor of our own summit success. We replicated the methodology in the original article as closely as possible.1,2 Climbers were blinded to all results to prevent psychological effects interfering with their success.
Our results are depicted in the Table. Although we acknowledge that our results are very limited owing to a small sample size, they do support those of the original article. Additionally, we can confirm that the test was easy to reproduce, simple to conduct, and required minimal infrastructure. These are important requirements for a screening test of this nature.
Pre and Post- 6MWT oxygen saturations at base camp and summit results
6MWT, 6-minute walk test.
In a recent Wilderness & Environmental Medicine letter, Daniels 3 stated that the 6MWT was not predictive of summit success on Mount Kilimanjaro. Unfortunately, owing to a lack of detailed methodology and insufficient sample size, a comparison between the original results and the Kilimanjaro results is not possible. However, this illustrates the potential use and easy reproducibility of this test in other remote environments.
In conclusion, we observed that the 6MWT is an easily reproducible test that deserves further robust investigation as a screening tool for extreme altitude summit success. Further research with greater sample sizes is essential to determine the reliability of 6MWT is predicting summit success.