Comparison of Heart Rate statistical parameters from Photoplethysmographic signal in resting and exercise conditions

The aim of this article is to investigate the possibility of computing Heart Rate Variability (HRV) indices from the finger Photoplethysmogram. To indicate that whether Pulse Rate Variability (PRV) from PPG signal can be used as an alternative to Heart Rate Variability (HRV) from ECG signal. The Photoplethsmographic (PPG) and Electrocardiographic (ECG) signals from 33 participants were recorded simultaneoussly during resting and exercise conditions. The peaks of PPG and R-waves of ECG were detected and reconstructed to the Peak-to-Peak interval (PPI) and R-to-R interval (RRI) waveforms respectively. In both conditions, the mean and standard deviation (SDNN) of the intervals over 5 minutes were computed from the two waveforms. Results from cross correlation between PPI and RRI show that the average correlation coefficients (r) are higher in resting than the “r” in exercise. In regression analysis of the statistical parameters between RRI and PPI, the determination coefficients (R²) of the means are close to one in both conditions, whereas the R² of SDNN in exercise is lower than the one in resting. This finding suggests that the HRV indices can be evaluated from PPG with reliability during the rest.