Wearable-Sensor-Based Physical Activity and Sleep in Children with Down Syndrome Aged 0-5 Years: A Systematic Review.

Wearables enable objective measurement of physical activity (PA) and sleep. Studies that have examined PA and sleep in children with Down syndrome (DS) have not been systematically reviewed. The objectives of this systematic review (PROSPERO: CRD420251036478) were to: (1) describe patterns of PA and sleep in children with DS; (2) compare PA and sleep between DS and non-DS; and (3) evaluate sensor data collection procedures. Searches were conducted in PubMed, Scopus, Web of Science, Embase, and SPORTDiscus, with the last search on 7 October 2025. Risk of bias was assessed with the Joanna Briggs Institute tools. From 203 records, 9 original studies were included. Children with DS (n = 8-66 participants; 1-67 months) showed small changes in movement rates over time and greater upper- than lower-limb movements. Segment-specific counts and time spent on high-intensity activity were lower in DS than non-DS. Overall, children with DS exhibited poor sleep quality, sleeping approximately one hour less than controls and 3-7 h below global recommendations. Sensor data collection protocols varied in epoch length (15-30 s), attachment site (wrist, ankle, and hip), and device model. Population-based research employing standardized sensor procedures is warranted to better establish PA levels and sleep quality in children with DS.