The Oura ring can track your sleep by monitoring your body's movements, and it uses that data to determine the stages of your sleep (light, deep, REM) and it also will give you a Sleep score, which gives you an idea of the overall quality of your sleep, and it also gives you an idea of the readiness you have the following day.
It also tracks your activity level throughout the day, counting steps and measuring calorie burn, and it also gives you a daily activity score, which takes into account your step count, calories burned, and duration of moderate-to-vigorous activity.
It also gives you a summary of your recovery and readiness in the morning, which takes into account your sleep, activity, and heart rate variability, so you can see how well your body is recovering from the previous day's activities.
The data can be synced with an app on your phone, which allows you to view your progress over time and track your progress towards your goals. Additionally, it can also integrate with several popular fitness and health apps such as MyFitnessPal, Apple Health, Google Fit, etc.
Oura ring was first introduced in 2014 by the Oura Health, it has been recognized as a Medical Device by the FDA, being used in studies and research to track sleep, heart rate and body temperature patterns.
Overall, the Oura ring is a powerful tool for tracking various health and fitness metrics and can be used to improve your sleep, activity, and overall wellness.