Objective.—Maximum aerobic capacity decreases at high altitude. This study was conducted to compare the changes in maximum aerobic capacity in men and women mountaineering trainees on induction to high altitude at 4350 m by trekking.

Methods.—Eight men and 8 women mountaineering trainees in a mountaineering course were selected for the study. The initial study was conducted at 2100 m (586 mm Hg) and then during 6 to 7 days of sojourn at 4350 m (435 mm Hg). Maximum oxygen consumption (Vo_2max), maximum heart rate (HR_max), pulse arterial oxygen saturation (Sao₂), and maximum ventilation (VE_max) were measured.

Results.—Vo_2max, HR_max, duration of work (minutes), and Sao₂ saturation decreased significantly (P < .05) with increasing altitude in both sexes. Conversely, VE_max and ventilatory equivalent (VE/ Vo₂) increased significantly (P < .05). Men showed a relatively higher value of maximum exercise variables (total exercise time, exercise intensity, and Vo₂) than women trainees at both altitude locations. The decrement of Vo_2max was 13% in women and 17% in men (P < .05).

Conclusions.—The results indicate that the decrement of maximum aerobic capacity at 4350 m was less in women than in men under similar modes of ascent.