[The wavelet-analysis of non-stationary heart rate variability during out head-up tilt test]

Heart rate variability (HRV) during the head-up tilt test (HUT) was investigated using an automated set of dynamic positioning in the gravitational field. The theory of wavelets is applied to find the dynamics of changes in the spectral properties of rhythmogran during the transitional phases of HUT. Quantitative parameters (spectral integrals, instantaneous maximal frequencies, nonstationarity factors), that describe transitive stages of such non-stationary head-up tilt test, are calculated.