Nakamura Y, Yamamoto Y, Muraoka I
Department of Sports Sciences, Waseda University, Saitama, Japan.
J Appl Physiol (1985). 1993 Feb;74(2):875-81. doi: 10.1152/jappl.1993.74.2.875.
The objectives of the present study were to investigate autonomic nervous system influence on heart rate during physical exercise and to examine the relationship between the fractal component in heart rate variability (HRV) and the system's response. Ten subjects performed incremental exercise on a cycle ergometer, consisting of a 5-min warm-up period followed by a ramp protocol, with work rate increasing at a rate of 2.0 W/min until exhaustion. During exercise, alveolar gas exchange, plasma norepinephrine (NE) and epinephrine (E) responses, and beat-to-beat HRV were monitored. HRV data were analyzed by "coarse-graining spectral analysis" (Y. Yamamoto and R. L. Hughson. J. Appl. Physiol. 71: 1143-1150, 1991) to break down their total power (Pt) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low-frequency (0.0-0.15 Hz) and high-frequency (0.15-0.8 Hz) components, from which low-frequency and high-frequency power (Pl and Ph, respectively) were calculated. Parasympathetic (PNS) and sympathetic (SNS) nervous system activity indicators were evaluated by Ph/Pt and Pl/Ph, respectively. From the fractal component, the fractal dimension (DF) and the spectral exponent (beta) were calculated. The PNS indicator decreased significantly (P < 0.05) when exercise intensity exceeded 50% of peak oxygen uptake (VO2 peak). Conversely, the SNS indicator initially increased at 50-60% VO2peak (P < 0.05) and further increased significantly (P < 0.05) at > 60% VO2peak when there were also more pronounced increases in NE and E.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是调查自主神经系统在体育锻炼期间对心率的影响，并检验心率变异性（HRV）中的分形成分与该系统反应之间的关系。10名受试者在自行车测力计上进行递增运动，包括5分钟的热身期，随后是斜坡方案，工作速率以2.0瓦/分钟的速度增加直至力竭。在运动期间，监测肺泡气体交换、血浆去甲肾上腺素（NE）和肾上腺素（E）反应以及逐搏HRV。HRV数据通过“粗粒化频谱分析”（Y. 山本和R. L. 休森。《应用生理学杂志》71: 1143 - 1150, 1991）进行分析，以将其总功率（Pt）分解为谐波和非谐波（分形）成分。谐波成分进一步分为低频（0.0 - 0.15赫兹）和高频（0.15 - 0.8赫兹）成分，据此计算低频和高频功率（分别为Pl和Ph）。副交感神经（PNS）和交感神经（SNS）系统活动指标分别通过Ph/Pt和Pl/Ph进行评估。从分形成分中计算分形维数（DF）和频谱指数（β）。当运动强度超过峰值摄氧量（VO2峰值）的50%时，PNS指标显著下降（P < 0.05）。相反，SNS指标在VO2峰值的50 - 60%时最初增加（P < 0.05），在> 60% VO2峰值时进一步显著增加（P < 0.05），此时NE和E也有更明显的增加。（摘要截断于250字）
