ACUTE EFFECTS OF WALKING ON SERUM-LIPIDS AND LIPOPROTEINS IN WOMEN

The purpose of this study was to characterize and evaluate the acute effects of walking performed of fairly light (50% VO2max) and moderate (70% VO2max) intensities on serum lipids and lipoproteins in a group of premenopausal (n=11) and a group of postmenopausal (n=10) women, Premenopausal women were (x+/-SE(M)) 34.5+/-1.1 years of age, had 22.8+/-1.7% body fat and a 2.47+/-0.08 l . min(-1) VO2max. Postmenopausal women were 54.8+/-2.5 years of age, had 37.9+/-0.9% body fat and a 2.06+/-0.15 l . min(-1) VO2max. All subjects walked on a motor-driven treadmill at each respective intensity of exercise for a total duration sufficient to expend 350 kcal of energy, Dependent variables included total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and its subfractions HDL(2)-C and HDL(3)-C, low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), Blood samples were obtained at baseline (pre-exercise), immediately post-exercise (IPE), and at 24 hours and 48 hours post-exercise, A repeated measures design was employed controlling for diet, menstrual cycle periodicity, natural menopause, and plasma volume shifts, A 2x4 ANOVA was used to test for differences among means for each group separately, Significant (p<0.05) time exercise intensity interactions were found for TC and LDL-C for the premenopausal women, This non-parallel change across exercise intensity condition created significant differences at IPE for both TC and LDL-C, Furthermore, an IPE increase in TG (p<0.05) was observed, For the postmenopausal women, a significant (p<0.05) timexexercise intensity interaction was noted for LDL-C, Non-parallel changes across intensity level at IPE were responsible for this interaction, A 19.8% increase HDL(2)-C (p<0.05) at IPE was also noted, No other differences were found for either group, These findings indicate that a single bout of walking has the potential to acutely affect the blood lipid profile of premenopausal as well as postmenopausal women, Immediately following a walk performed at 70% VO2max, reduction in LDL-C was noted for both groups of women while the 50% VO2max condition increased HDL(2)-C only in the post-menopausal women.