THE INDEPENDENT EFFECTS OF EXERCISE AND ESTROGEN ON LIPIDS AND LIPOPROTEINS IN POSTMENOPAUSAL WOMEN

Objective: To assess the effects of a moderate exercise program with a nd without oral estrogen replacement on levels of lipids and lipoprote ins in postmenopausal women. Methods: One hundred one postmenopausal w omen were randomized into four groups: control or sedentary (N = 20), exercise alone (N = 25), estrogen replacement using 0.625 mg conjugate d equine estrogen (N = 28), and exercise supplemented with conjugated equine estrogen (N = 28). The exercise groups were placed on a moderat e exercise program. Following baseline testing, each group returned at 3 and 6 months for cardiorespiratory fitness testing and serum lipid and lipoprotein profiles. Results: We found a significant decrease in systolic blood pressure (P < .05) in all treatment groups. The maximum oxygen uptake increased by 9.0 and 7.8% in the exercise and conjugate d equine estrogen/exercise groups, respectively, compared to the other groups (P < .05). These responses were seen at both 3 and 6 months. T otal exercise time (time spent on the treadmill until exhaustion durin g testing) significantly increased in the exercise group by 21% (P < . 01). Exercise alone was associated with significant decreases in total cholesterol (5.2%, P < .05), triglycerides (2%, P < .05), and low-den sity lipoprotein (LDL) cholesterol (10%, P <.01), and a significant in crease in the high-density lipoprotein (HDL) cholesterol-LDL ratio (17 .2%, P < .01). Significant changes were noted in these values, as well as increases in HDL cholesterol (16 and 14.8%; P < .01) and apolipopr otein A(1) (25.6 and 26.5%; P < .001) in the conjugated equine estroge n and conjugated equine estrogen/exercise groups, respectively. Howeve r, there were no differences in the changes observed in the conjugated equine estrogen groups with versus without exercise. No direct correl ation was seen between measures of exercise performance and the change s seen in lipids and lipoproteins. Conclusions: Estrogen therapy alone had the greatest beneficial effect on lipids and lipoproteins. Exerci se alone resulted in a significant reduction in cholesterol, triglycer ides, and LDL cholesterol, and an increase in the HDL-LDL ratio. Howev er, combined conjugated equine estrogen and exercise did not demonstra te an added improvement in lipid metabolism. Physical fitness levels i ncreased in the exercise groups, but not in the control group or the e strogen-alone treated women.