The effect of low-dose oral contraceptives on cardiorespiratory function, coagulation, and lipids in exercising young women: A preliminary report

Abstract A study was undertaken to determine whether low-dose oral contraceptive usage would negate the beneficial effect of exercise on cardiorespiratory fitness, lipid and lipoprotein levels, and coagulation. Twelve exercising women were randomly allocated to groups of either oral contraceptive users or non-oral contraceptive users. When compared with results in the control group, maximal oxygen uptake (ml/kg 1 · min 1 ) decreased significantly in the oral contraceptive users during the 6-month period of observation. This was associated with an 8% decrease in both the oxygen uptake (2.34 to 2.17 L/min) and the oxygen pulse (12.1 ± 3.2 to 11.2 ± 2.2 ml/beat). The serum cholesterol, triglycerides, high-density lipoprotein/cholesterol, and high-density lipoprotein subfractions 2 a and 2 b levels were not altered. A significant increase in plasminogen activity was found in the oral contraceptive users: values increased from a coherent time average of 3.8 ± 0.5 U/ml at baseline to 5.7 ± 0.7 U/ml at 6 months; values returned to baseline levels 1 month after stopping the oral contraceptives (coherent time average of 3.9 ± 0.6 U/ml; p