Fitness trackers - tools of self-quantification - come in a variety of form factors, but most are strapped onto the wrist, masquerading as a watch that is often both a tribal badge and a tool.

The specifics of these tools tend to vary, but they’ll often track sleep and heart rate, and record this back to an app for later digestion.

This year a Finnish company released a fitness tracker in a relatively novel form factor: a ring. To my knowledge, there’s one other product in this category, a Motiv ring (now a second-generation product).

What does the Ōura offer?

Via various interpretations of HR data, the Oura attempts to give the wearer a picture of their ‘readiness’, or how hard one should push oneself. If the wearer has had a sequence of good nights’ sleep, and appropriately active days, the ring will tell the wear to ‘go all out’.


This guidance is derived from monitoring during sleep, which makes the Oura a very, very small form-factor sleep tracker. Accelerators in the ring track movement, and two IR LEDs allow a photosensor to gauge heart rate, heart rate variance, resting heart rate, and change in body temperature. Measurements based on HR are only done when at rest - mostly when sleeping - which helps extend the battery life (it lasts for about a week), and remove the motion artefacts that are the bane of oHR devices.

Is it any good?

  • Sleep tracker: yes. Having used Garmin (5x, 5x Plus) and Suunto (9) devices, the ring’s sleep start detection is good. It’s not as good at tracking wake up time (I think it’s waiting for a ‘big’ accelerometer event that signifies getting out of bed) as the Suunto 9, and I think it’s too sensitive about tracking waking up during the night (or I don’t realise I’m waking up).
  • HR, RHR, HRV: yes. Comparing its guidance to that from HRV4Training, it’s on par. but has the benefit that it doesn’t require a measurement every day, as it’s spent the previous night gathering the measurements.
  • Respiration rate: I have no devices to compare this too, but it feels right.
  • Current performance condition/activity guidance: yes. Again, like HRV4Training, it considers not only the most recent data, but historic data, to deliver guidance. As this is primarily based on heart rate variance, it is susceptible to drugs that artificially alter that. If, for example, I went for a vigorous four-hour bike ride, and took a muscle relaxant at bed time, its advice the next day would be compromised.

A feature I particularly like of the ring is that it doesn’t consider just its data, but defers to better sources when available. When I go for a bike ride, I leave the ring at home, and instead of seeing a period of inactivity, it sees the bike ride that my Wahoo has just written to Apple Health: for an activity tracker to survive, it has to be able to read data from outside its walled garden, something very few are willing to do. Continuing the interoperability trend, there is both an API and a JSON data export, and a web portal to view the data that has been collected.

How could it be improved?

  • Two-factor authentication for the cloud portal, not using SMS.
  • IFTTT integration.
  • On-demand measurements. The ring can track periods of rest through the day, but one is relying on the accelerometers to trigger this. If I’m going to have a nap, or meditate, I’d like to be able to trigger the recording to start when I start.

Long-term update

I stopped using it, simply because after going back to a Garmin (Forerunner 945) from an Apple Watch, I was getting duplicate data (I find the body battery on the 945 as useful as the data from the ring), and a firmware update introduced a bug that made the battery drain in ~22h (not 7 days). I know, I should have opened a ticket with their support, but after not wearing a ring for a couple of days, I remembered how nice unencumbered fingers are.

The Ōura is an excellent companion to an Apple Watch: it captures sleep data very well, and provides useful day-to-day guidance.