Hautala Arto J, Mäkikallio Timo H, Seppänen Tapio, Huikuri Heikki V, Tulppo Mikko P
Merikoski Rehabilitation and Research Center, Oulu, Finland.
Clin Physiol Funct Imaging. 2003 Jul;23(4):215-23. doi: 10.1046/j.1475-097x.2003.00499.x.
Methods based on non-linear heart rate (HR) dynamics have been suggested to probe features in HR behaviour that are not easily detected by the traditional HR variability indices. This study tested the hypothesis that analysis of correlation properties of R-R intervals provides useful information on HR fluctuation during exercise. High- (HF) and low-frequency (LF) spectral components and a short-term scaling exponent (alpha1) of HR variability, were analysed for nine healthy subjects at rest, during incremental and steady-state exercise, during atropine infusion and during incremental exercise after atropine administration. During the incremental exercise test alpha1 increased from rest to an intensity level of approximately 40% of VO2max (from 1.07+/-0.24 to 1.50+/-0.25, P<0.001) and thereafter decreased linearly until the end of exercise (from 1.50+/-0.25 to 0.38 +/- 0.10, P<0.001). Atropine infusion increased the scaling exponent alpha1 value from 0.91+/-0.23 to 1.37+/-0.31 (P<0.001). During exercise after atropine infusion, a linear reduction was observed in the scaling exponent alpha1 from 1.37+/-0.23 to 0.25+/-0.08 (P<0.001). Analogous changes in alpha1 were seen during long-term steady-state exercise compared to incremental exercise. Conventional HR variability indices did not show any significant changes during exercise at high exercise intensity levels. alpha1 correlated with the LF/HF ratio at rest (r=0.90, P<0.001), but the correlation was weaker after atropine (r=0.71, P<0.05) and during exercise (e.g. r=0.33, P=NS at the level of 40% of VO2max). In conclusion, incremental exercise test until exhaustion results in bidirectional changes in correlation properties of R-R interval dynamics. These changes can be explained by the intensity of vagal and sympathetic input to the sinus node during the different intensity levels of exercise. Changes in alpha1 values can be detected also in high intensity levels, when the conventional measures of HR variability can not be applied.
基于非线性心率（HR）动力学的方法已被提出，用于探究传统心率变异性指标不易检测到的心率行为特征。本研究检验了以下假设：分析R-R间期的相关性可提供运动期间心率波动的有用信息。对9名健康受试者在静息状态、递增运动和稳态运动期间、阿托品输注期间以及阿托品给药后的递增运动期间，分析了心率变异性的高频（HF）和低频（LF）频谱成分以及短期标度指数（alpha1）。在递增运动试验期间，alpha1从静息状态增加到约为最大摄氧量（VO2max）40%的强度水平（从1.07±0.24增加到1.50±0.25，P<0.001），此后线性下降直至运动结束（从1.50±0.25下降到0.38±0.10，P<0.001）。阿托品输注使标度指数alpha1值从0.91±0.23增加到1.37±0.31（P<0.001）。在阿托品输注后的运动期间，观察到标度指数alpha1从1.37±0.23线性下降到0.25±0.08（P<0.001）。与递增运动相比，长期稳态运动期间alpha1也有类似变化。常规心率变异性指标在高运动强度水平的运动期间未显示任何显著变化。alpha1在静息状态下与低频/高频比值相关（r=0.90，P<0.001），但阿托品给药后相关性较弱（r=0.71，P<0.05），运动期间相关性也较弱（例如，在VO2max的40%水平时r=0.33，P=无显著性差异）。总之，递增运动试验直至疲劳会导致R-R间期动力学相关性的双向变化。这些变化可以用不同运动强度水平下迷走神经和交感神经对窦房结的输入强度来解释。当无法应用传统的心率变异性测量方法时，在高强度水平下也能检测到alpha1值的变化。
