Oura, the company behind one of the most popular smart rings on the market, is facing a proposed class action lawsuit over its sleep tracking accuracy claims, TechCrunch reports. The complaint, filed in a California district court, argues that Oura rings cannot capture the physiological signals that define real sleep cycles, such as eye movement and brain activity. Instead, plaintiffs say the device relies on indirect measurements to estimate sleep stages.
What the Lawsuit Claims
According to the complaint, Oura has promoted several generations of its ring by emphasizing their sleep-tracking precision. The company markets its latest device, the Oura Ring 5, as delivering 95% sleep staging accuracy compared to a clinical sleep lab. Plaintiffs argue this comparison is misleading, since Oura’s sensors can’t record the same data a formal sleep study captures through polysomnography.
The lawsuit also claims Oura’s AI models estimate sleep stages using indirect signals rather than direct physiological measurements. It alleges the company discloses this limitation only in technical documentation that most customers never read, while its broader marketing — including celebrity partnerships and influencer campaigns — leaves that caveat out entirely.
Legal Action and Requested Remedies
The lawsuit seeks to establish a class of affected customers and asks the court for an injunction to stop what it describes as false advertising. It also requests monetary compensation for buyers who purchased Oura rings based on the accuracy claims in question.
Oura Pushes Back on the Allegations
Oura disputes the lawsuit’s claims. In a statement to Gizmodo, the company said multiple studies have validated its sleep-staging technology against polysomnography, and stressed that Oura has never marketed the ring as a medical device or a substitute for a clinical sleep study.
The company also pointed to its research foundation, noting that its sleep-staging algorithm draws on more than 1,200 nights of collected data and is described in a published paper explaining how the ring’s sensors inform its results. Oura said independent, third-party studies back its accuracy claims and confirmed it intends to contest the lawsuit in court.
How Oura Rings Actually Measure Sleep
Unlike the multi-sensor setup used in a clinical sleep study, the Oura Ring 5 works with a smaller toolkit. It uses a photoplethysmogram sensor with red and green LEDs to track heart rate, blood oxygen levels, and breathing patterns, along with a temperature sensor and an accelerometer that monitors movement overnight.
Missing from that list are the tools used in true polysomnography — sensors that track brain activity, eye movement, heart electrical activity, and muscle activity. Because Oura doesn’t collect these signals directly, its software estimates sleep stages from the data it can gather and builds a sleep score from that analysis.
A Growing Challenge for the Wearables Industry
Oura isn’t alone in facing this gap between marketing and measurement. Many wearable makers operate in a regulatory gray area, offering wellness insights that studies can support but that fall short of medical-grade diagnosis. Oura has occupied that space for years without major legal pushback.
That may be changing as the company grows. Oura has reported strong ring sales and rising revenue in recent years and is reportedly preparing for a future IPO. As scrutiny of the company increases alongside its market presence, this lawsuit could signal more challenges ahead.
