Oral contraceptives, exercise, and acute mountain sickness in women

Background Previous research has found that exercise exacerbated acute moun tain sickness (AMS) in men. Purpose: The current study tested this relation ship in women taking oral contraceptives. Methods: We studied seven women a t 428 mmHg for 10 h; once while at rest (R) and once while performing inter mittent exercise (EX). Results. AMS scores had a slight increase at 9 vs, 0 h at altitude in both trials (p < 0.05). Resting measurements of ventilati on (VE), arterial oxygen saturation (SPO2), end tidal O-2 (PETO2), and end tidal CO2 (PETCO2) were not different over time or between trials (p > 0.05 ). While fluid intake did not change, urine output increased during the 0-3 h period, regardless of trial, and returned to baseline values by the 6-9 h period (218 +/- 37 vs. 121 +/- 22 ml . h(-1); p < 0.05). During exercise, SPO2 significantly dropped compared with similar time points in R (73.1 +/ - 1.1 vs. 85.7 +/- 1.8%; p < 0.05). Despite exercise-induced desaturation, the AMS scores were not significantly different between R and EX. Conculsio n: These results suggest that oral contraceptives may cause a compensation for the physiological responses to exercise critical for the development of AMS.