Deriving Accurate Nocturnal Heart Rate, rMSSD and Frequency HRV from the Oura Ring

We evaluated the accuracy of Oura ring-derived HR and HRV measures against ECG, and found that accurate HRV measures can be obtained from Oura’s PPG-derived signals with a stringent validity proportion threshold of around 80% for each 5 min segment and aggregating over time windows of at least 30 min.