The first Oura ring analyzes the quality of your rest and recovery while you sleep by continuously monitoring your heart rate (optically), pulse amplitude, respiratory rate, body temperature, and even the slightest hand and finger movements. Oura uses these parameters to determine the state of your brain while you sleep.
While you're awake, the ring monitors the duration and intensity of your activities, and your inactive time using a 3D accelerometer.
- Photoplethysmogram (PPG): During sleep, your Blood Pulse Volume is measured from the arteries on the palm side of the finger with infrared LEDs. The little bumps in the ring band house the infrared LED transmitter and receiver.
- Motion: A 3D accelerometer is used to monitor your activity during the day. During the night it is used to identify different stages of sleep.
- Temperature: The Oura ring tracks the variations of your body temperature by measuring your skin temperature each night.
Oura uses these physiological data signals to calculate when you are in deep sleep, light sleep, REM sleep, and awake states. It uses this information together with your daytime activity data to assess the degree to which you have recovered from mental and physical challenges and your readiness to perform going forward.