Oura Ring

Tool Infobox
Related topics	HRV (Heart Rate Variability), Activity tracking, Sleep tracking, Body temperature tracking, Heart rate tracking
Linked pages on this wiki	Projects (4), People (2)

The Oura Ring is a wearable that is worn on a finger as a ring which tracks sleep, activity and readiness. Since 2013 there have been three different versions of the ring, with the latest version (v3) being launched in November 2021. At the same time they changed their business model, requiring a monthly subscription for access to all metrics recorded.

While the sensor set of the rings have changed over the versions, generally they contain an accelerometer, a temperature sensor as well as an optical heart rate sensor. From these sensors the Oura calculates the following metrics:

A generation 3 Oura Ring, showing some of the sensors on the inside of the ring

Differences between models

Model	Sleep tracking	Activity tracking	Readiness tracking	Heart rate during sleep	Heart rate during day	Body temperature	Menstrual cycle tracking	Blood oxygen tracking
Generation 1 [citation needed]	✔	✔	✔	✔	❌	✔	❌	❌
Generation 2	✔	✔	✔	✔	❌	✔	❌	❌
Generation 3	✔	✔	✔	✔	✔	✔	✔	✔

Metrics provided

• Heart rate related: Resting Heart Rate, Heart Rate Variability, Respiratory Rate
• Body Temperature (relative changes, not absolute)
• Sleep (total sleep, sleep phases throughout the night)
• Activity (calorie burn, steps, walking distance 'equivalent')

Body temperature metrics

Oura does not report the absolute temperature recordings (neither through the phone app, nor through API data exports). Instead it provides two ways of reporting relative changes.

The daily view of body temperature displays how the average nightly body temperature compares to the average of all body temperature readings done in the past, thus comparing it to the baseline body temperature as recorded over time. As a result the average and median of all recordings will always be zero0.

The trend view of the body temperature is a bit more complicated. Oura states that "the trend view displays a weighted average of how your body temperature varies from your baseline based on a three-day window" and that "days closed to the current date will have more of an impact on your readings". Oura does not disclose the details of how the weighting of records is done and as such it is not possible to really understand or recreate how the company arrives at these values. One observation is that the trend values tend to be slightly biased towards positive values, probably as the distribution of possible body temperatures is not fully normally distributed, but rather censored on the lower end.

Use for menstrual cycle tracking

The rings of the 3rd generation include an Oura internal beta-test for cycle tracking. Furthermore, since mid-2022 the Natural Cycles app – a cycle tracking app that's cleared for use as birth control – can use the temperature data from the ring as main input to predict fertile time windows.

Exporting data

As for most wearables, there is unfortunately no (easy) way to access all raw data from the device. But Oura offers a way to download at least all of your calculated metrics from the Oura Cloud web interface. Beyond this, they also offer an API to automate access to Oura data in third party tools. An example implementation is the Oura integration into Open Humans, which automatically fetches the latest data at multiple times throughout the day and which since December 2022 gets data both from version 1.0 and 2.0 of the Oura API.

In January 2022, Oura announced a version 2.0 of their API for exporting data. While it was under development this new API only provides access to more detailed activity data (such as intra-day heart rate), but as of December 2022 detailed information about readiness and sleep are also available. For now the version 1.0 of the API still works and is scheduled to be sunset at some unspecified time in early 2023.

Subscription

When Oura released the 3rd generation of their ring, they announced that they would introduce a monthly subscription model that is priced at $5.99 before tax in the USA, €5.99 after tax in the EU and $6.99 after tax for the rest of the world. For users of a 3rd generation ring, the subscription is necessary to get full access to all the metrics the ring records. Early adopters were offered a 'free' lifetime subscription when upgrading to a 3rd generation ring at release at the end of 2021. Users of earlier generations are not required to switch to the subscription model. Oura has been criticized for introducing the subscription model at a time where the promised new features of the 3rd generation (see above) were not yet released. In June 2022 the blood oxygen tracking has still not been released.

Project using Oura Ring

Given the different kinds of sensors used in the Oura Ring, a diverse set of projects have been done with it:

• Bastian Greshake Tzovaras has
  • used it alongside time-tracking data from RescueTime and geolocation-data from Overland to understand the impact of COVID-19 lockdowns on himself.
  • compared sleep data between the Oura Ring and Fitbit.
  • looked at how smoking impacts his (resting) heart rate as measured by Oura.
• Herman de Vries has explored the relationship between HRV, sleep and physical activity by using an Oura Ring
• Beni Kmoz used 800 days of Oura data, hierarchical clustering and principal component analysis to understand how menstrual cycle and physical activity explain the data.