Wearables for Physical Activity Guideline Development and Health Surveillance: Converging Research and Practice Agendas

Objective : Etiological epidemiology and health surveillance are interdependent foundations of physical activity research, yet wearable devices have been adopted disproportionately across these 2 pillars of policy and practice. As physical activity research transitions from mostly self-reports toward a combination of mostly wearables and some self-reports, alignment between etiological evidence generation and surveillance systems is becoming increasingly important. We examine the goals, methods, and emerging convergence between wearable-based policy, surveillance, and etiological epidemiology. Methods : This narrative review compares the wearable-based methods and metrics used for physical activity surveillance and for etiological research and draws on 2 contrasting case studies: the World Health Organization’s surveillance-oriented standardization work and the harmonized research infrastructure of the Prospective Physical Activity, Sitting, and Sleep consortium. Building on these case studies and emerging evidence, we outline a 10-year roadmap toward a globally harmonized and translation-ready wearable evidence ecosystem. Results : Wearables capture high-resolution dimensions of physical activity including the intensity, accumulation patterns, and 24-hour composition of movement that questionnaires cannot resolve. Wearable-based studies have identified strong dose–response associations at substantially lower absolute activity volumes than currently recommended in national and global guidelines and enabled the emergence of novel behavioral phenotypes including activity fragmentation, movement timing, and physical activity micropatterns. However, substantial challenges remain, including methodological heterogeneity, incompatibility between questionnaire- and wearable-derived evidence, limited representation of low- and middle-income countries, and uncertainty around translation into surveillance and guideline frameworks. World Health Organization surveillance initiatives prioritize simple, scalable, and internationally comparable metrics, whereas etiological epidemiology can accommodate greater complexity and methodological innovation. Conclusions : Convergence between surveillance and etiological epidemiology is both feasible and necessary, but requires harmonized wear protocols and reporting standards, capacity building and equitable infrastructure in underrepresented communities, and clear translation pathways between research-grade and policy-grade wearable metrics.