An intervention study to assess potential effect and user experience of an mHealth intervention to reduce sedentary behaviour among older office workers

Background Office workers spend a high percentage of their time sitting, often in long periods of time. Research suggests that it is healthier to break these long bouts into shorter periods by being physically active. Objective We evaluated the effect of a context-aware activity coach, called the PEARL app, an mHealth intervention that provides activity suggestions, based on a physical activity prediction model, consisting of past and current physical activity and digital agendas. Method Fifteen office workers, aged 50+, participated in an intervention study in which they used the intervention for 1 week, preceded by a 1-week baseline period. Measurements were taken before and after the intervention period. Results 107 days of data from 14 participants were analysed. Total sedentary time was not reduced as a result of using the intervention (baseline vs intervention: 47.8±3.6 vs 46.8±3.0, n.s.). When using the intervention, participants reduced their total time spent in long sitting bouts (≥45 min) from 19.3 to 14.4 min per hour of wear time (p<0.05). Participants indicated that the main value of the intervention lies in creating awareness about their personal sedentary behaviour pattern. Conclusion An mHealth service has the potential to improve the sedentary behaviour of older office workers, especially for breaking up long sedentary periods. Focusing on total sedentary time as an outcome of an intervention, aimed at reducing sedentary behaviour, is too simplistic. One should take into account both the duration and the number of bouts when determining the effect.