WalkMore: a randomized controlled trial of pedometer-based interventions differing on intensity messages

Background: Pedometer-based programs have elicited increased walking behaviors associated with improvements in blood pressure in sedentary/low active postmenopausal women, a population at increased risk of cardiovascular disease. Such programs typically encourage increasing the volume of physical activity with little regard for its intensity. Recent advances in commercially available pedometer technology now permit tracking of both steps/day and time in moderate (or greater) intensity physical activity on a daily basis. It is not known whether the dual message to increase steps/day while also increasing time spent at higher intensity walking will elicit additional improvements in blood pressure relative to a message to only focus on increasing steps/day. The purpose of this paper is to present the rationale, study design, and protocols employed in WalkMore, a 3-arm 3-month blinded and randomized controlled trial (RCT) designed to compare the effects of two community pedometer-based walking interventions (reflecting these separate and combined messages) relative to a control group on blood pressure in sedentary/low active post-menopausal women, a population at increased risk of cardiovascular disease. Methods/Design: 120 sedentary/low active post-menopausal women (45-74 years of age) will be randomly assigned (computer-generated) to 1 of 3 groups: A) 10,000 steps/day (with no guidance on walking intensity/speed/cadence; BASIC intervention, n = 50); B) 10,000 steps/day and at least 30 minutes in moderate intensity (i.e., a cadence of at least 100 steps/min; ENHANCED intervention, n = 50); or a Control group (n = 20). An important strength of the study is the strict control and quantification of the pedometer-based physical activity interventions. The primary outcome is systolic blood pressure. Secondary outcomes include diastolic blood pressure, anthropometric measurements, fasting blood glucose and insulin, flow mediated dilation, gait speed, and accelerometer-determined physical activity and sedentary behavior. Discussion: This study can make important contributions to our understanding of the relative benefits that walking volume and/or intensity may have on blood pressure in a population at risk of cardiovascular disease.