Exercise during the Menstrual Cycle: Variations in Physiological Baselines

Abstract

Abstract Eighteen healthy undergraduates, free of any acknowledged menstrual disorders, performed a standard bicycle ergometer exercise on the first and the fourteenth day of the month under controlled environmental conditions. Postabsorptive measurements were made of blood hemoglobin, blood hematocrit, heart rate, and blood pressures at rest and following exercise. Heart rate and systolic blood pressures taken at rest varied significantly between all the experiments, regardless of time relative to the menstrual cycle. Resting blood hemoglobin and hematocrit, however, varied significantly relative to the time of the experiment with respect to the menstrual cycle. All measurements made following the exercise failed to show a statistical significance between experiments. The results suggest that variations in blood hemoglobin and hematocrit are related to the menstrual cycle at rest but apparently are completely masked by a moderate bout of exercise. The physiological bases of the cyclic changes and the exe...