Comparison group
The comparison group used a minimal app version across the eight study weeks, which sent them two daily reminders. At customized times in the morning, they were reminded to wear the Fitbit and at customized times in the evening, they were reminded to sync their step data with the Fitbit app and to charge their Fitbit device. The reminder in the evening was chatbot-based to make sure the comparison group used the app at the same frequency as the treatment group.