Three-Minute Step Test for Predicting Acute Mountain Sickness: A Post Hoc Analysis of Rhodiola Crenulata Extract for Prevention of Acute Mountain Sickness, a Randomized, Double-Blind, Placebo-Controlled, Crossover Trial.

Background: Acute mountain sickness (AMS) often occurs in individuals who rapidly travel above 2,500 m. As the convenience of traveling and the development of mountain sports increase, AMS will become an increasingly important public health problem. However, no method to effectively predict AMS before it occurs is currently available.

Methods: This post hoc study investigated whether the 3-Minute Step Test (3MST), which evaluates physical fitness, is predictive of AMS development. The data collected in "Rhodiola crenulata extract for prevention of AMS: a randomized, double-blind, placebo-controlled, crossover trial" was used in the analysis. This study collected 204 observations of 102 participants who made two ascents of Hehuan Mountain (3,100 m) by bus within a 3-month period. Participants completed the 3MST at 250 m (before ascent) and 3,100 m (on Hehuan Mountain). The presence of AMS was accessed using the Lake Louise scoring system.

Results: AMS was identified in 124 observations (60.78%). In the univariate analysis, the pre-departure 3MST score (at 250 m) was not significantly associated with AMS ( = 0.498), but the 3MST score measured at 3,100 m, ascent number, pulse rate at 3,100 m, and saturation of peripheral oxygen (SpO) measured at 3,100 m were significantly correlated with the occurrence of AMS ( = 0.002, 0.039, 0.005, < 0.001, respectively). In a further multivariate analysis, only SpO measured at 3,100 m had a significant association with AMS ( = 0.016 and 0.006, respectively). The trend analysis showed that for every 1-point increase in the 3MST score at 3,100 m, the AMS decreased by 4% (adjusted odds ratio [AOR] = 0.96, 95% confidence interval [CI] = 0.92-1.01).

Conclusion: The 3MST score cannot be a predictor of AMS, but it may have a potential role in predicting ascent safety in high-altitude areas.