Active 10: Brisk walking to support regular physical activity

We describe a methodology and a technology supporting an intervention carried out by Public Health England (PHE) to encourage physically inactive people (doing less than 30 minutes' physical activity per week) to initiate regular physical activity via 10 minutes of daily brisk walking. The intervention is designed to encourage the inclusion of short bouts of continuous brisk walking in everyday activities such as shopping or commuting. To this extent a behaviour change mobile application, Active 10, was developed and distributed freely for Android and iOS. The app was downloaded over 620,000 times and our server infrastructure has collected nearly a billion data points between March 2017 and January 2019. The paper describes the rationale for Active 10, the application supporting the intervention, the data architecture and the data collection approach. Then we discuss the complexity of developing a health tracking technology with such large number of users, producing a significant volume of data. Finally, we describe a preliminary data analysis, focussing on a cohort of 129,010 users who used the app for over 8 weeks: 73% of these users achieved less than ten minutes of brisk walking per day during the first week; by the end of the 8th week this subset of users showed, on average, a 10-fold increase in brisk walking. The most inactive section of the cohort, the 54% of users who showed virtually no brisk walking activity during week 1, seems to achieve the greatest proportional increase, and by the end of week 8 they appear to meet, on average, 10 minutes of continuous brisk walking per day. The increase is more evident within the 15% of the cohort who kept the app for over six months: on average a 12% increase in average activity was observed in this group with no sign of decline.