A workplace-based intervention to increase levels of daily physical activity: the Travel to Work cluster RCT

Background: There may be opportunities for working adults to accumulate recommended physical activity levels (≥ 150 minutes of moderate-intensity physical activity in bouts of ≥ 10 minutes throughout the week) during the commute to work. Systematic reviews of interventions to increase active transport indicate that studies are predominantly of poor quality, rely on self-report and lack robust statistical analyses. Objectives: To assess the effectiveness, cost and consequences of a behavioural intervention to increase walking during the commute to work. Design: A multicentre, parallel-arm, cluster randomised controlled trial incorporating economic and process evaluations. Physical activity outcomes were measured using accelerometers and GPS (Global Positioning System) receivers at baseline and the 12-month follow-up. Setting: Workplaces in seven urban areas in south-west England and south Wales. Participants: Employees (n = 654) in 87 workplaces. Interventions: Workplace-based Walk to Work promoters were trained to implement a 10-week intervention incorporating key behaviour change techniques. Main outcome measures: The primary outcome was the daily number of minutes of moderate to vigorous physical activity (MVPA). Secondary outcomes included MVPA during the commute, overall levels of physical activity and modal shift (from private car to walking). Cost–consequences analysis included employer, employee and health service costs and consequences. Process outcomes included barriers to, and facilitators of, walking during the daily commute. Results: There was no evidence of an intervention effect on MVPA at the 12-month follow-up [adjusted difference in means 0.3 minutes, 95% confidence interval (CI) –5.3 to 5.9 minutes]. The intervention cost was on average, £181.97 per workplace and £24.19 per participating employee. In comparison with car users [mean 7.3 minutes, standard deviation (SD) 7.6 minutes], walkers (mean 34.3 minutes, SD 18.6 minutes) and public transport users (mean 25.7 minutes, SD 14.0 minutes) accrued substantially higher levels of daily MVPA during the commute. Participants who walked for ≥ 10 minutes during their commute were more likely to have a shorter commute distance (p