Oura Ring Sleep Score Alternative

Oura Ring calculates a 0–100 Sleep Score by combining seven weighted contributors: total sleep time, sleep efficiency (time asleep vs. time in bed), restfulness (movement and wake-ups), REM sleep duration, deep sleep duration, sleep latency (time to fall asleep), and sleep timing (alignment with your circadian rhythm). The ring uses infrared PPG sensors for high-fidelity pulse waveform capture, a 3D accelerometer for movement and sleep stage detection, and an NTC skin temperature sensor for circadian rhythm tracking. Finger-based PPG captures arterial pulse signals with higher signal-to-noise ratio than wrist-worn devices, resulting in more accurate sleep stage classification.