Acute mountain sickness (AMS) typically peaks following the first night at high altitude (HA) and resolves over the next 2-3 days, but the impact of active ascent on AMS is debated. To determine the impact of ascent conditions on AMS, 78 healthy Soldiers (mean±SD; age=26±5yr) were tested at baseline residence, transported to Taos, NM (2845m), hiked (n=39) or were driven (n=39) to HA (3600m), and stayed for 4 days. AMS-Cerebral Factor Score (AMS-C) was assessed at HA twice on day 1 (HA1), five times on days 2 and 3 (HA2 and HA3) and once on day 4 (HA4). If AMS-C was ≥0.7 at any assessment, individuals were AMS susceptible (AMS+;n=33); others were non-susceptible (AMS─;n=45). Daily peak AMS-C scores were analyzed. Ascent conditions (active vs. passive) did not impact the overall incidence and severity of AMS at HA1-HA4. The AMS+ group, however, demonstrated a higher (p<0.05) AMS incidence in the active versus passive ascent cohort on HA1 (93 vs. 56%), similar incidence on HA2 (60 vs. 78%), lower incidence (p<0.05) on HA3 (33 vs. 67%), and similar incidence on HA4 (13 vs. 28%). The AMS+ group also demonstrated a higher (p<0.05) AMS severity in the active versus passive ascent cohort on HA1 (1.35±0.97 vs. 0.90±0.70), similar score on HA2 (1.00±0.97 vs. 1.34±0.70), and lower (p<0.05) score on HA3 (0.56±0.55 vs. 1.02±0.75) and HA4 (0.32±0.41 vs. 0.60±0.72). Active compared to passive ascent accelerated the time course of AMS with more individuals sick on HA1 and less individuals sick on HA3 and HA4.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.