A Micro-randomized Trial of HeartSteps, an mHealth Intervention for Increasing Physical Activity

HeartSteps is an Android-based mHealth intervention that contains two main intervention components: contextually-tailored suggestions for activity and planning of the next day's activity. Activity suggestions provide individuals with actionable suggestions for how they can be active in their current context. Delivered suggestions are tailored based on time of day, user's location, day of the week (weekend/weekday), and weather. HeartSteps can deliver a user activity suggestions up to five times a day. Evening planning asks users to create or choose a plan of how they will be active on the following day. Planning can be delivered once a day, in the evening.