Oura Ring: According to the study, it clearly outperforms Apple Watch when it comes to sleep tracking – but there are limitations

Wearables now offer quite comprehensive sensor technology. Cheaper smartwatches now not only measure heart rate, but can also measure your fitness level and analyze your own sleep in terms of sleep duration and sleep quality. A current study compares the quality of this detection between different wearables, specifically the third generation Oura Ring, the Fitbit Sense 2 and the Apple Watch Series 8.

The study included thirty-five test subjects. The experimental setup was comparatively simple: the study participants wore the Apple Watch, the Sense 2 and the Oura Ring for one night. In addition, polysomnography was carried out, which offers extensive monitoring of sleep and body functions and is the reference method in this regard. All of the study participants had at least no diagnosed sleep disorders.

There were clear differences between the individual devices, even though the sleep monitoring worked quite well overall. All devices were able to differentiate between waking and sleeping phases with a sensitivity of over 95 percent. However, there were clear differences when differentiating between individual sleep phases – including in terms of the consistency of the results. The Apple Watch Series 8 was both more precise and more sensitive than the other two devices, although not for all users. According to the study, in this comparison the Oura Ring did not show any deviation from the reference method in terms of awake time, deep, light and REM sleep, but the Fitbit Sense overestimated the time of light sleep and underestimated the time of deep sleep phases. The Apple Watch, on the other hand, underestimated waking times and even significantly underestimated deep sleep – and then overestimated light sleep phases.

The Oura-funded study has some limitations. Only people without diagnosed sleep disorders were included in the study, but such sleep monitoring could actually make sense especially for people with sleep disorders. It is also unclear how current devices – in particular the Apple Watch Series 10 and the fourth generation Oura Ring – would perform. In May we already reported on a study carried out on other wearables, which also showed significant deviations.