Changes in physical activity and health outcomes in a population-based cohort of mid-life Australian-born women.

Cross-sectional studies and intervention programs have suggested that physical activity is a potential contributor to the health and wellbeing of mid-life and older women. This prospective longitudinal study investigates whether natural changes in physical activity are associated with changes in health outcomes in a population-based cohort of Australian-born women aged 45-55 years living in Melbourne. Of the 352 women from the Melbourne Women's Midlife Health Project who filled in a base-line physical activity questionnaire, 292 (83 per cent) were evaluated around three years later with regard to physical activity, psychological wellbeing, self-rated health, symptoms experienced, body mass index (BMI), blood pressure and serum lipids. Mean (SD) physical activity measured at base-line was 5.9 (5.7) hours/week, or 1496 (1449) kcal/week; mean (SD) change in physical activity per week was 0.05 (5.24) hours, or 44 (1347) kcal, indicating that although mean change was small there was substantial variation in change. There were significant increases in BMI (P < 0.001), wellbeing (P < 0.05), the number of reported menopause-related symptoms, and high-density lipoprotein cholesterol (HDL-C) levels (P < 0.001), and a decrease in low-density lipoprotein cholesterol (LDL-C) levels (P < 0.05). Change in level of physical activity was positively associated with change in HDL-C (P < 0.01) and change in wellbeing (P = 0.08) and negatively associated with change in coronary heart disease risk score. By increasing physical activity in mid-life, women may reduce at least one risk factor (HDL-C) associated with coronary heart disease.