The spectral properties and synchronization of low-frequency (LF) oscillations during the tilt test were studied for the heart rate variability (HRV) and the finger photoplethysmogram (PPG) of healthy subjects. Dynamics of the LF oscillations in the PPG and synchronization strength between the HRV and the PPG were found to be inhomogeneous among healthy subjects, which suggest existence of individual differences in characteristics of adaptive reactions of the cardiovascular autonomic control.
The paper is devoted to the analysis of dynamic of interactions between signals of autonomic circulatory regulation. We investigated two-hour experimental records of 30 healthy people. Phase synchronization was studied using the signals of the electrocardiogram and the photoplethysmogram of vessels. We found the presence of long synchronous intervals in some subjects. For analysis of the dynamic we calculated autocorrelation functions. The analysis made it possible to reveal indirect signs of the influence of the humoral regulation system.