An umbrella review of systematic reviews of the impact of wrist-worn wearables on health outcomes.

We conducted an umbrella review to synthesize the evidence on the effectiveness of interventions incorporating wrist-worn wearables* feedback on diverse health outcomes including health promotion (i.e., health behaviors and disease risk perception) morbidity, mortality, functioning, and other health-related metrics in humans. We searched in MEDLINE, Web of Science, Embase and Cochrane Library until 18th March 2025 for eligible systematic reviews. After screening 9 487 citations, we identified 39 systematic reviews, which included 98 original studies (one observational study, 95 randomized controlled trials, and two pre-post studies). The reviews primarily focused on adult populations, individuals with cardiometabolic conditions, and cancer survivors. The original interventional studies mainly included Fitbit (40.2%), Polar (12.4%), and ActiGraph (10.3%) devices. Over 80% of the clinical trials involved complex behavioral interventions with wearable-based feedback, and the control groups varied. Most systematic reviews were rated as low confidence, with common flaws including inadequate considerations for risk-of-bias and heterogeneity. Interventions incorporating wrist-worn activity trackers increased physical activity in diverse populations. The effect of interventions incorporating wrist-wearables' feedback on cardiometabolic risk markers, quality of life, depression/anxiety and pain was limited and remained inconsistent. Our findings rely on existing systematic reviews, which may vary in quality, review methodologies and comprehensiveness. There is also potential for missing more recent evidence not yet captured in these reviews. These limitations should be considered when interpreting our results. Acknowledging these caveats, wrist-worn wearables seem to increase physical activity, and may have also additional benefits that require further study.