Class action questions Oura Ring sleep-tracking accuracy

A California proposed class action accuses Oura of overstating the accuracy of its sleep-tracking, arguing the sleep-stage results rely on AI estimates based on finger signals rather than clinical sleep-staging sensors and that some results have little more than a coin flip’s chance of being correct. The suit cites a 2025 study showing 53.18% sleep-stage accuracy, contrasts with Oura’s prior 79% and 95% claims, and seeks to stop the misleading claims and restitution for affected customers, naming Oura Ring 5, Ring 4, and Ring 4 Ceramic.