Lawsuit Says Oura Ring Overstates How Well It Tracks Sleep

A lawsuit filed August 20, 2026 in San Francisco claims Oura rings guess sleep stages from body signals like heart rate rather than measuring brain activity directly. The complaint says Oura advertised 95% accuracy but real results are about as reliable as a coin toss. Oura, which filed for a stock market listing in May 2026, has not commented.