Update: An Oura spokesperson reached out to us and shared the following statement:
“We stand behind our science, research, and accuracy claims.
Like other consumer sleep wearables, Oura Ring estimates sleep stages using multiple physiological signals, including heart rate, heart rate variability, movement, breathing patterns, and temperature. There is well-documented, peer-reviewed independent scientific evidence that sleep stages are associated with distinct, measurable, reproducible changes in physiology, which is why these signals are reliably used to classify sleep stages.
While Oura Ring is not a medical device or a substitute for a clinical sleep study, Oura’s sleep staging has been validated and compared favorably in several studies against polysomnography, the gold standard. The data collection that informs the creation of Oura’s sleep staging algorithm (NSSA) is unparalleled in sleep research with over 1,200 nights of data collected, and we published a peer-reviewed paper that describes how the sleep-staging algorithm was developed and how it uses the signals collected by the ring. Multiple third-party, independent studies support our claims of accuracy and we have transparently reported on the mechanisms and measures that inform Oura’s sleep staging.
We’re committed to continuing to clearly communicate what Oura measures, what it estimates, and how members should use that information. We dispute the allegations and will defend against them in the appropriate legal forum.”
The original story is as follows:
Oura has built much of its reputation around helping people understand what happens while they sleep. Its rings provide an overall Sleep Score each day, alongside estimates for light, deep, and REM sleep. A new proposed class-action lawsuit is now questioning just how much confidence people should put in those numbers.
Filed on August 20 in the U.S. District Court for the Northern District of California, the complaint accuses Oura of misleading customers by advertising highly accurate sleep-stage tracking despite relying on signals from the wearer’s finger rather than directly measuring brain activity.
Oura has previously claimed 79% agreement with gold-standard polysomnography (PSG) when identifying wake, light, deep, and REM sleep. More recently, marketing cited in the complaint claimed 95% sleep-staging accuracy compared with a clinical sleep lab.
The lawsuit argues those numbers may give customers the wrong idea about what the ring can actually measure. A clinical sleep study looks at things such as brain waves, eye movement, and muscle activity. Oura instead estimates sleep stages using heart rate, heart-rate variability, movement, skin temperature, and blood-oxygen trends on newer models.
The complaint also points to a 2025 Nature study involving 45 patients across 45 nights. The Oura Ring correctly identified sleep stages 53.18% of the time, according to the study. It underestimated light sleep by 13.84 minutes and deep sleep by 5.98 minutes, while REM sleep was overestimated by 31.56 minutes.
The case was brought by California resident Madison Surber, who paid $513.68 for an Oura Ring 4 Gold in May 2025. She says Oura’s marketing led her to believe the ring could accurately track her sleep stages and claims she would not have bought it, or would have paid less, if she had known about its limits.
The lawsuit is seeking class-action status, damages, restitution, and changes to Oura’s advertising. Oura has pushed back against the claims. In a statement provided to USA Today, the company said, “We dispute the allegations in this complaint and intend to defend against them.”
For people relying on an Oura Ring every night to understand their sleep, such a large gap between the advertised accuracy and the figure cited in independent research is cause for concern.
The OnePlus Buds Clip are a new pair of open-ear earbuds built around a simple convenience. They join Sony’s LinkBuds Clip in the growing ear-cuff category, but either OnePlus bud can go on either ear.
Sensors recognize how the earbuds are being worn and route the audio channels accordingly. There’s no label to check before putting them on, and the feature also works when only one bud is used.
We buy fitness bands and activity trackers to keep tabs on our exercise, but it is easy to forget to start tracking or switch modes when moving between different activities. For Fitbit and Pixel Watch users, that could soon become a lot less annoying, as Google is rolling out a major upgrade to automatic activity tracking that can recognize more than 100 types of exercise, up from just 10 before.
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