Experimental Observation of the Self-Oscillatory Dynamics of the Regulation Contours of the Cardiovascular System

In this work, we experimentally study the heart rate variability, photoplethysmograms, and electroencephalograms of healthy subjects in the course of active experiments with respiration, whose rate varied according to a known law. On the basis of the experimentally measured signals of the heart rate variability, photoplethysmograms, and electroencephalograms, it is shown that the low-frequency regulation processes with frequencies below 1 Hz interact with each other and are significantly influenced by the respiration process. The obtained results are indicative of the presence of several vegetative-regulation centers whose activity is manifested in the low-frequency dynamics of the signals of the heart rate variability, photoplethysmograms, and electroencephalograms.