An observational study on glycemic trajectories during ascent, stay, and descent in a 45-day high-altitude exposure

To characterize glycemic dynamics and heterogeneity in response patterns during a 45-day high-altitude expedition among healthy adults.

In this longitudinal observational study, eight healthy adults underwent continuous glucose monitoring (CGM) during ascent (2,800 to 4,531 m), stay, and descent. Glycemic metrics (mean glucose, variability indices, time-in-range) were analyzed across altitude-defined phases. Unsupervised clustering was employed to identify glycemic response patterns.

Mean glucose exhibited a mild U-shaped trend, with transient elevation and peak glycemic variability (CV = 17.3%) at extreme altitude. Time-in-range remained >97%. Cluster analysis revealed two distinct patterns: a stable, low-variability group (Cluster 1) and a high-variability group (Cluster 2) with amplified excursions and delayed recovery.

Short-term high-altitude exposure induces mild, reversible disturbances in glucose regulation, with significant inter-individual heterogeneity. CGM effectively captures these dynamic changes and identifies distinct adaptive patterns, highlighting its utility for monitoring metabolic stress and population-specific responses in extreme environments.