heart rate variability
respiration rate variability
time domain analysis
O.V. Melnik, A.A. Mikheev
Functional status – a complex of properties, determining the level of life of the organism, the system re-sponse to physical and psychological burden, which reflects the degree of integration of functions and the adequacy of work performed. At the present time to assess the functional states of RM Baevsky concept was developed about the use of the circulatory system as an indicator of adaptive reactions of the whole organism. At the same tool to assess the functional state of the acts, heart rate variability (HRV). In less developed physiological aspects and the mathematical apparatus of the respiratory rhythm, marked variability which is a marker of failure to adapt. Analysis of time relations of the respiratory cycle would study the mechanisms of central regulation of breathing and use the data to assess functional status.
To improve the diagnostic efficiency of the functional state proposed a parallel study of the parameters of heart rate and respiration. Correlation studies of the power spectra of signals of breathing and rhythmogram allow most visually assess the features of the functioning and the degree of synchronized regulatory mechanisms. It is established that a high cross-correlation relation between the parameters of respiration and heart rate observed in well-adapted individuals. In addition, changing the value of cross-correlation of the frequency reflects the contribution of the parasympathetic and sympathetic regulatory mechanisms in the current functional status.
To study the degree of synchronization of the cardiovascular and respiratory systems in real time is proposed dynamic estimate of the coefficient of cross-correlation between signal and rhythmogram breathing in time domain. As between the response of the cardiovascular system and change the regime or the phase of respiration there is a physiological delay in the direct calculation of the coefficient of cross-correlation between two signals is not sufficiently informative. Propose a procedure for an adaptive search for a maximum coefficient of cross-correlation in a moving time window of fixed duration. Controlled parameter is the trend of the maximum cross-correlation coefficient during the test. This ratio not only allows to monitor the coherence of the reaction of the cardiovascular and respiratory systems in stress tests, but is a marker of the functional state of the organism as a whole, since it