Wearable Activity Tracker-Based Interventions for Physical Activity, Body Composition, and Physical Function Among Community-Dwelling Older Adults: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: The global aging population faces great challenges. Wearable activity trackers have emerged as tools to promote physical activity among older adults, potentially improving health outcomes. However, the effectiveness of such interventions on physical activity, body composition, and physical function among community-dwelling older adults remains debated. Objective: This study conducted a systematic review and meta-analysis to evaluate the impact of wearable activity tracker-based interventions on physical activity, body composition, and physical function among community-dwelling older adults. Methods: We searched the PubMed, Embase, Web of Science, and CENTRAL databases from inception until January 2025 to identify related randomized controlled trials. The outcomes were focused on physical activity (physical activity time, daily step count, and daily sedentary time); body composition (BMI and body fat); and physical function (timed up and go test and chair stand test). Subgroup analysis by different controls (usual care or conventional interventions) and different follow-ups (immediate Results: In total 23 trials with 4566 participants were eligible for analysis. Compared to usual care, there was lo- to moderate-certainty evidence that the wearable activity tracker-based interventions significantly increased physical activity time (standardized mean difference [SMD]=0.28, 95% CI 0.10-0.47; P=.003) and daily step counts (SMD=0.58, 95% CI 0.33-0.83; P<.001) immediately after intervention, while no significant improvements were observed in daily sedentary time (mean difference [MD]=-1.56, 95% CI -10.88 to 7.76; I-2=0%; P=.74). These interventions were at least as effective as conventional interventions but did not show superiority. Compared with usual care, the interventions using wearable activity trackers only demonstrated a notable increase in daily step count over short-term follow-up (SMD=0.23, 95% CI 0.11-0.36; P<.001). As for body composition and physical function, there was low- to moderate-certainty evidence that the wearable activity tracker-based interventions did the timed up and go test (MD=0.14, 95% CI -0.87 to 1.16; P=.78), or the chair stand test (SMD=-0.31, 95% CI -0.62 to 0; Conclusions: This systematic review and meta-analysis indicate that wearable activity tracker-based interventions were effective in enhancing physical activity with low to moderate certainty, but did not significantly impact body composition or physical function, with low to moderate certainty, among community-dwelling older adults, particularly immediately after intervention. This intervention showed a more pronounced impact when compared to usual care, rather than to conventional interventions, with low to moderate certainty. It is important to notethat this intervention showed moderate-certainty evidencetoward improving daily step count, supporting its sustained impact during short-term follow-up.