Oral Contraceptive Use May Attenuate Menstrual Cycle-InducedVentilatory Changes in Endurance Trained Runners

摘要

The relationship between two menstrual cycle phases and cardio respiratory fitness in athletes on oralcontraceptives and not on oral contraceptives was assessed in a pilot study. Twelve endurance-trained college crosscountry runners underwent maximal oxygen consumption treadmill testing, during the late follicular/ovulatory phase andlate luteal/premenstrual phase of their menstrual cycle. No significant differences were detected in maximal oxygenconsumption between the oral contraceptive group and non-oral contraceptive group or between the two phases. Therewas a non-significant phase effect in the non-oral contraceptive group with maximal ventilation averaging 90.5±14.6L/min during the late follicular/ovulatory phase and decreasing to 79.1±9.8 L/min during the late luteal/premenstrualphase (p=0.102). Maximal ventilation was significantly lower by 15.6% between oral contraceptive and non-oralcontraceptive users during the late luteal/premenstrual phase (93.7+7.2 L/min vs 79.1+9.8 L/min, p=0.014, respectively).There was no significant phase effect in the oral contraceptive group for maximal ventilation. While oral contraceptive usewas associated with an attenuation of the negative effect of the late luteal/premenstrual phase on ventilator performance,there was no effect on maximal oxygen consumption.