1998 Volume 118 Issue 1 Pages 85-92
Power spectrum analysis of R-R intervals time series provides a noninvasive means of assessment of the regulatory activity of the autonomic nervous system. In this paper we examine the physiological sources of the very low frequency component (VLF In a range between 0.014Hz and 0.025Hz) of beat-to-beat fluctuations during periodic mental work load (MWL in mental arithmetic) and physical work load (PWL by bicycle ergometer). Mean amplitude of the VLF component is calculated from the DFT algorithm by area under VLF peak. We show that the periodic MWL and PWL evokes increase of the amplitude.