Estradiol and progesterone during exercise in healthy untrained women

Ten eumenorrheic nonathletic women, aged 21-25, were studied on the 8th day following the LH peak in three consecutive cycles. Plasma level and metabolic clearance rate (MCR) of estradiol (E2) and progesterone (P) were measured before and during a 2-h continuous treadmill test at a speed corresponding to 70% of their running speed at anaerobic threshold on three separate occasions. A significant decrease of plasma level of the hormones (-30% and -40%, respectively, P less than 0.01; mean) from resting values was found, while their metabolic clearance rate increased significantly [E2-MCR from 1017 l.d-1 to 1312 l.d-1 (+29%), P less than 0.001; mean; P-MCR from of 2061 l.d-1 to 2988 l.d-1 (+45%), P less than 0.003; mean]. The increase in MCR of the two hormones was significantly correlated with the increase in heart rate and systolic blood pressure accompanying the beginning of the exercise test.