Clean interbeat intervals
Robust R-peak detection on ambulatory ECG and quality-checked PPG beat detection, using our open-source ecg2rr, E2E-PPG and pyPPGqa tools.
Heart rate and HRV from clean beats, not noisy guesses.
HRV is only as good as the interbeat intervals behind it. We assess signal quality first, then compute the full set of HRV metrics and follow them over days, months or a whole pregnancy.
What we deliver
Heart rate and HRV analytics, end to end.
All three HRV families
Time domain (SDNN, RMSSD), frequency domain (LF, HF and their ratio) and nonlinear measures (SD1, SD2 and entropy), matched to the recording length each metric needs.
Respiration rate
Breathing rate estimated from smartwatch PPG and accelerometry with a transfer learning approach.
Long-term trends
Nocturnal and daily heart rate and HRV across weeks and months, as in our pregnancy and postpartum studies.
Risk stratification
Models that use longitudinal heart rate and HRV to stratify risk, such as preterm birth.
Device accuracy
Accuracy assessments of consumer devices against ECG, as in our Samsung smartwatch and Oura ring studies.
How we analyze it
- Signal quality assessment before feature extraction
- Deep learning R-peak detection and PPG reconstruction
- Time, frequency and nonlinear HRV analysis
- Mixed-effects models and machine learning for outcomes
What you receive
- Beat-level and window-level HRV tables
- Trend figures per participant and cohort
- Validation statistics and a methods section
- Documented, reproducible code
Evidence
Selected peer-reviewed work by our team.
- Sarhaddi et al. A comprehensive accuracy assessment of Samsung smartwatch heart rate and heart rate variability. PLOS ONE, 2022. doi:10.1371/journal.pone.0268361
- Cao et al. Accuracy assessment of Oura ring nocturnal heart rate and heart rate variability in comparison with electrocardiography in time and frequency domains: comprehensive analysis. Journal of Medical Internet Research, 2022. doi:10.2196/27487
- Sarhaddi et al. Trends in heart rate and heart rate variability during pregnancy and the 3-month postpartum period: continuous monitoring in a free-living context. JMIR mHealth and uHealth, 2022. doi:10.2196/33458
- Feli et al. Preterm birth risk stratification through longitudinal heart rate and HRV monitoring in daily life. Scientific Reports, 2024. doi:10.1038/s41598-024-70773-0
- Sharifi-Heris et al. Heart rate variability and pregnancy complications: systematic review. Interactive Journal of Medical Research, 2023. doi:10.2196/44430
- Laitala et al. Robust ECG R-peak detection using LSTM. ACM SAC, 2020. doi:10.1145/3341105.3373945
- Kazemi et al. Respiration rate estimation via smartwatch-based photoplethysmography and accelerometer data: a transfer learning approach. Proc. ACM IMWUT, 2025. doi:10.1145/3712280