Is the Oura 4 ring more detailed in measured data provided?

Oura Ring 4 Data Measurement Detail

The Oura Ring 4 does not provide more detailed measured data than the Oura Ring Generation 3; both devices report identical sleep and cardiovascular metrics with comparable accuracy. 1, 2, 3

Measurement Accuracy Comparison

Heart Rate and Heart Rate Variability

• Both Oura Generation 3 and Generation 4 demonstrate nearly identical accuracy for nocturnal resting heart rate (RHR), with Generation 3 showing Lin's Concordance (CCC) = 0.97 and mean absolute percentage error (MAPE) = 1.67 ± 1.54%, while Generation 4 shows CCC = 0.98 and MAPE = 1.94 ± 2.51% 3
• For heart rate variability (HRV), Generation 4 slightly outperforms Generation 3 with CCC = 0.99 and MAPE = 5.96 ± 5.12% compared to Generation 3's CCC = 0.97 and MAPE = 7.15 ± 5.48%, though both demonstrate very high agreement with ECG gold standard 3
• Both generations show very high agreement for nightly average HR and HRV (r² = 0.996 and 0.980, respectively) with mean bias of -0.63 bpm and -1.2 ms when compared to medical-grade ECG 1

Sleep Measurement Capabilities

• Both Oura generations provide the same sleep metrics: total sleep time, sleep stages (Wake, Light, Deep, REM), and sleep duration, with strong correlation to sleep diary (r=0.82,95% CI 0.68-0.91) and mean absolute percentage error of 10% 4
• Sleep stage classification accuracy is identical between generations, with epoch-by-epoch analysis showing approximately 53% accuracy for multi-stage classification (Wake, Light, Deep, REM) in clinical populations 5
• Individual-level sleep measurements show substantial variability despite reasonable group-level averages, with total sleep time differences averaging below 12 minutes but individual-level differences often remaining large 5

Data Granularity and Reporting

Available Metrics (Both Generations)

• Nocturnal resting heart rate with high validity (r² = 0.996 with ECG) 1
• Time domain HRV parameters: RMSSD (root mean square of successive differences), SDNN (standard deviation of normal beat-to-beat intervals), AVNN (average of normal heartbeat intervals), pNN50 (percentage of successive intervals differing by >50ms) 2
• Frequency domain HRV parameters: low frequency (LF), high frequency (HF), and LF:HF ratio, though these show higher error rates 2
• Sleep staging: Wake, Light, Deep, and REM sleep classifications 5
• Physical activity metrics: steps, moderate-to-vigorous physical activity, total energy expenditure 4

Measurement Limitations (Both Generations)

• 5-minute interval measurements show higher error variance compared to average-per-night values, particularly for SDNN, LF, HF, and LF:HF ratio 2
• Physical activity measurements cannot replace research-grade accelerometers (ActiGraph), with mean absolute percentage errors exceeding acceptable thresholds for steps, moderate-to-vigorous physical activity, and total energy expenditure 4
• Sleep stage classification sensitivity ranges from 0.14 to 0.58 across different sleep stages, indicating substantial misclassification at the individual epoch level 5

Clinical Application Considerations

Validated Use Cases (Both Generations)

• Resting heart rate monitoring can potentially replace Actiheart measurements with only 3% mean absolute percentage error and 1 beat per minute average underreporting 4
• Sleep duration tracking can serve as alternative to manual sleep diary with 10% mean absolute percentage error 4
• Long-term lifestyle management for tracking trends in healthy adults, given high validity in nocturnal HR and HRV assessment 1

Critical Limitations for Clinical Use

• Individual-level inaccuracies prohibit use in clinical sleep medicine despite reasonable group-level agreement, as accurate assessment of individual nights is essential for patient care 5
• Complex bias patterns in ring-derived sleep metrics indicate that correction is non-trivial and device-specific 5
• Photoplethysmography susceptibility to motion artifacts and environmental noise requires careful interpretation in non-controlled settings 2

Practical Recommendations

For research or clinical applications requiring precise individual-night measurements, neither Oura generation provides sufficient accuracy 5. For population-level studies or personal wellness tracking where average trends over multiple nights are acceptable, both Oura Generation 3 and 4 perform equivalently 3. The Generation 4 offers marginal improvements in HRV accuracy (approximately 1% lower MAPE) but does not provide additional measured parameters or fundamentally different data granularity 3.