Effects of endurance exercise and hormone replacement therapy on serum lipids in older women

OBJECTIVE: To determine the effects of 11 months of exercise training and hormone replacement therapy (HRT), alone or in combination, on serum lipids and lipoproteins, in postmenopausal women. DESIGN: Controlled, prospective, 11-month clinical trial. Healthy postmenopausal women (n = 71, age range 60-72 yrs) were assigned to four groups in a 2 x 2 design (control, exercise, HRT, exercise + HRT). SETTING: Large, midwestern urban community; subjects were recruited from the community-at-large. The exercise program was conducted at a university exercise facility. INTERVENTIONS: HRT consisted of conjugated estrogens at 0.625 mg/day and trimonthly medroxyprogesterone acetate 5 mg/day for 13 days. Exercise consisted of 2 months of low intensity exercise followed by 9 months of vigorous exercise for 45 min/day, 3 or more days/week, at 65-85% of maximal heart rate. MEASUREMENTS: Maximal aerobic power (VO2 max), resting blood pressure, body composition, serum lipids and lipoproteins, and dietary intake at baseline and after 11 months. MAIN RESULTS: At the end of 11 months, subjects in the exercise group had decreased total cholesterol (TC; P < .01) and LDL-cholesterol (LDL-C; P < .05), but there was no change in HDL-cholesterol (HDL-C) or triglycerides. Women in the HRT group had decreased LDL-C (P < .001) and increased HDL-C (P < .01) and triglycerides (P < .01), but there was no change in TC. Exercise+HRT subjects had decreased TC (P < .05) and LDL-C (P < .001), and increased HDL-C (P < .001); exercise prevented the HRT-related increase in triglycerides. CONCLUSIONS: Endurance exercise training and HRT have independent and complimentary effects on serum lipid profiles in healthy postmenopausal women. Such effects are likely to reduce the risk of cardiovascular morbidity in this population.