Sleep tracking is designed to recognize when a user falls asleep, wakes up and record sleeps stages as they occur during the night. This includes light, deep and REM sleep stages.

Sleep and sleep stages are identified using a combination of heart rate, heart rate variability, respiration rate, body movement and other key inputs. Supported devices also enable body movement, respiration rate and oxygen saturation for a more complete picture.

The sleep score is a number (0-100) that summarizes the underlying data to reveal how a user slept. A high sleep score means that the user is well-prepared for the challenges of the day ahead.