Shin K, Minamitani H, Onishi S, Yamazaki H, Lee M
Department of Biomedical Engineering, Faculty of Science and Technology, Keio University, Yokohama, Japan.
Jpn J Physiol. 1995;45(6):1053-69. doi: 10.2170/jjphysiol.45.1053.
The purpose of this study was to assess the adaptive effects of endurance training on autonomic functions in athletes with spectral analysis of cardiovascular variability signals. Continuous ECG, arterial blood pressure (ABP), and respiratory signals were recorded from 15 athletes (VO2max > 55 ml/(kg.min)) and 15 nonathletes (VO2max < 45 ml/(kg.min)) in the sitting position during controlled respiration (tidal volume 700 ml and 15 cycles/min). The autonomic functions were assessed by the normalized low-frequency power (LF power: 0.06-0.14 Hz) and high-frequency power (HF power: the region of the respiratory frequency based on respiratory spectrum) obtained from the autospectra of the RR interval, systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) variability signals. The spontaneous baroreflex sensitivity (BRS) was evaluated by the moduli, BRSLF and BRSHF, of the transfer function between the RR interval and SAP variability in LF and HF bands. The resting HR in athletes was significantly lower than that in nonathletes. In the case of RR interval spectra, the HF power was significantly higher in athletes than in nonathletes, whereas the LF power was significantly lower in athletes than in nonahtletes. These differences might reflect an alteration of sympathovagal interaction with a predominance of parasympathetic activity. However, there was no significant difference in the LF power of SAP and DAP autospectra, reflecting the sympathetic vascular control. The BRSLF and BRSHF were significantly higher in athletes as compared with nonathletes. These results indicate that endurance training induces autonomic imbalance (i.e., the enhanced vagal activities/the attenuated sympathetic tone), which may in part contribute to the resting bradycardia and an increase in the spontaneous BRS in athletes.
本研究旨在通过心血管变异性信号的频谱分析，评估耐力训练对运动员自主神经功能的适应性影响。在控制呼吸（潮气量700 ml，每分钟15次呼吸周期）的坐姿状态下，记录了15名运动员（最大摄氧量>55 ml/(kg·min)）和15名非运动员（最大摄氧量<45 ml/(kg·min)）的连续心电图、动脉血压（ABP）和呼吸信号。通过从RR间期、收缩期动脉压（SAP）和舒张期动脉压（DAP）变异性信号的自谱中获得的归一化低频功率（LF功率：0.06 - 0.14 Hz）和高频功率（HF功率：基于呼吸频谱的呼吸频率区域）来评估自主神经功能。通过LF和HF频段中RR间期与SAP变异性之间传递函数的模量BRSLF和BRSHF来评估自发性压力反射敏感性（BRS）。运动员的静息心率显著低于非运动员。就RR间期频谱而言，运动员的HF功率显著高于非运动员，而运动员的LF功率显著低于非运动员。这些差异可能反映了以副交感神经活动占主导的交感迷走神经相互作用的改变。然而，反映交感神经血管控制的SAP和DAP自谱的LF功率没有显著差异。与非运动员相比，运动员的BRSLF和BRSHF显著更高。这些结果表明，耐力训练会引起自主神经失衡（即迷走神经活动增强/交感神经张力减弱），这可能部分导致了运动员的静息心动过缓和自发性BRS增加。
