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Typical plain three-dimensional chart of a spectral analysis of heart-rate variability during orthostatic load in the non-cardiac autonomic reactivity group.
Notes: The frequency of fluctuations in R-R intervals (Hz) is given on the x-axis; power spectral density (PSD; ms2/Hz) on the y-axis; and time (s) on the z-axis. T1: supine-1, T2: standing, T3: supine-3.
