Heart rate variability analysis during bicycle ergometer exercise

Abstract

During exercise the concomitant increase of arterial pressure and heart rate indicates that arterial baroreflex control of the heart period is modified. It has been shown that during dynamic exercise heart rate increases are due to both a parasympathetic withdrawal and an augmented sympathetic activity. Aim of this study is to investigate the role of the pedaling action on heart rate variability signals. Six healthy subjects underwent a 4-phases exercise, consisting of active and passive cycling, and active and passing muscle contraction, at fixed frequencies. ECG (I lead) and pedaling frequency signals (when present) were acquired by using a commercial acquisition board. Heart rate variability signal has been analyzed by performing the spectral analysis of RR interval series (resampled at 4 Hz). We found that during a bycicle ergometer exercise at 100 W there is a spectral component at the pedaling frequency in the HRV spectrum only if it is present in the spectrum of the body movement series. Also, stimulation of the mechano and/or chemosensitive receptors of the gastrocnemious muscle elicited in our experiment was not sufficient to activate the cardiovascular control regions.