Abstract
BACKGROUND: Mobile health (mHealth) interventions are increasingly used to promote individual well-being. Mobile applications provide accessible, personalized tools for monitoring and improving health, thereby fostering the adoption of positive behaviors. Nonetheless, further evidence is needed to support the effectiveness of mHealth programs. The present study aims to evaluate the effectiveness of a protocol designed to increase daily step counts, grounded in the Health Action Process Approach (HAPA). METHODS: The protocol was delivered via the MyPocketHealth app, developed by the research team, and incorporated different communication strategies. Participants were involved in setting a goal and choosing between a personalized or a standardized goal (7,000 daily steps), which could be reviewed at any time. Moreover, they received either interactive (HAPA-I: group 1) or non-interactive (HAPA-NI: group 2) daily notifications promoting the target behavior through HAPA constructs for 15 days, while also monitoring their daily steps (self-monitoring). A third group engaged solely in self-monitoring without receiving any communication (no-communication group; No comm). Goal attainment was reinforced through badge awards (rewards). A sample of 210 healthy, physically inactive participants aged 22 to 55 underwent the intervention. RESULTS: Significantly higher dropout rates were recorded in the HAPA-NI group compared to the other experimental conditions. However, participants in the HAPA-NI and HAPA-I groups showed gradual increases in daily step counts relative to baseline throughout the intervention period. Conversely, participants in the No-communication group showed a marked increase in daily step counts relative to baseline during the initial phase of the intervention, which progressively declined over time. CONCLUSION: These findings suggest that theory-driven notifications effectively promote sustained engagement in achieving behavioral goals, and that it is crucial to optimize the balance between notification frequency and interactivity when designing mHealth interventions to improve user engagement and ensure long-term effectiveness.