Dose-response to exercise in women aged 45-75 yr (DREW): Design and rationale

Physical inactivity in postmenopausal women contributes to a rise in atherogenic risk factors associated with the metabolic syndrome. Although regular physical activity positively contributes to health, inactivity progressively increases with age. The Dose Response to Exercise in Women aged 45-75 yr (DREW) study is designed to investigate the effect of different amounts of exercise training on cardiorespiratory fitness and risk factors for cardiovascular disease (CVD) in postmenopausal women at moderately increased risk of CVD. DREW will recruit 450 sedentary, healthy, postmenopausal women with a body mass index of 25-40 kg.m-2, resting systolic blood pressure (BP) of 120-159 mm Hg, and a resting diastolic BP of < or = 99 mm Hg. Laboratory and self-report measures completed at baseline and 6 months include maximal oxygen consumption (.VO2max), resting BP, anthropometry, dietary habits, physical activity history, medication use, menstrual history, personal and family medical history, and fasting HDL cholesterol, LDL cholesterol, triglycerides, and glucose. Eligible participants are randomly assigned to a nonexercise group or one of three exercise groups. Participants exercise 3 to 4x wk-1 at a heart rate equivalent to 50% of .VO2max expending 4, 8, or 12 kcal.kg-1.wk-1, depending on group assignment. This study will allow quantification of possible dose-response relations (50%, 100%, and 150% of the consensus physical activity recommendation) between exercise training and study outcomes. DREW can make important contributions to our understanding of the effects of physical activity in postmenopausal women and help refine public health and clinical recommendations for this group.