A formalized criterion of cardiorespiratory synchronization for assessment of dynamic changes in autonomic homeostasis

A comparative study was performed to analyze the diagnostic efficiency of a proposed cardiorespiratory coefficient (CRC) for assessment of dynamic changes in autonomic homeostasis. In the two series of the study, 45 healthy male volunteers were examined using models of emotional tension and acute graded hypoxia. Under stress-inducing conditions, both cardiorespiratory synchronization reflecting the degree of autonomic balance and the changes in the cardiorespiratory system substantially depended on the individual parameters recorded at baseline, specifically, the autonomic tone and the degree of hypoxic resistance. It was found that cardiorespiratory changes could be detected rather quickly during the first minutes of testing if assessed by the CRC changes during test exercises. This allows the accuracy and selectivity of analysis of changes in the integral parameters of autonomic regulation to be increased and the CRC to be recommended as a forecasting criterion for analyzing autonomic homeostasis and autonomic reactivity in humans.