Effects of Endurance Training on Autonomic Function in Highly Fit Men: Spectral Analysis of Cariovascular Variability Signals

摘要

By auto- and cross-spectral analysis of RR interval and arterial blood pressure (ABP) variabilities, effects of endurance - training on autonomic function were investigated in 15 highly-fit (FG:Vo_(2max)>55 ml/minkg) and 15 unfit (UG:Vo_(2max) < 45 ml/minkg) men under the condition of controlled respiration (15 breaths/min and 700ml V_T). The resting HR in FG was significantly (p < 0.001) lower than that in UG. The high-frequency (HF) power (an index of cardiac vagal tone) in RR interval spectra was significantly (p < 0.001) higher in FG than in UG. The low-frequency (LF) power (an indicator of cardiac sympathetic activities) of RR interval spectra in FG was significantly (p < 0.05) lower as compared to UG. The spontaneous baroreflex sensitivity (BRS), as assessed by the moduli of the transfer function between RR interval and systolic blood pressure variabilities, was significantly (p < 0.05) higher in FG. These results indicate that endurance training induces a predominant parasympathetic activities in autonomic balance, which may contribute in part to the resting bradycardia and an enhancement in the spontaneous BRS in FG.