Javorka Michal, Zila Ivan, Balhárek Tomás, Javorka Kamil
Department of Physiology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic.
Clin Physiol Funct Imaging. 2003 Jan;23(1):1-8. doi: 10.1046/j.1475-097x.2003.00460.x.
During physical exercise, heart rate (HR) increases by parasympathetic withdrawal and increase of sympathetic activity to the heart. HR variability (HRV) in time and frequency domains provides information about autonomic control of the cardiovascular system. Non-linear analysis using the Poincaré plot method is able to reveal supplementary information about cardiac autonomic control. The aim of this study was to determine the association between HRV parameters, the initial increase of HR at the onset of exercise (on-response) and HR decrease in the recovery phase after acute exercise (off-response). HR was continuously monitored in 17 healthy male subjects (mean age: 20.3 +/- 0.2 (SEM) years) at rest (25 min supine; 5 min standing), during exercise (8 min of step test at 70% of maximal power output) and in the recovery phase (30 min supine). HRV analysis in time and frequency domains and evaluation of the Poincaré plot measures (length, widths) were performed on selected segments of HR time series. HR on- and off-responses were quantified using an exponential curve fitting technique. The time constants T(on) and T(off), representing the rate of on- and off-responses to exercise, were computed. Postexercise HRV indices and time constant of on-response - T(on) - to exercise were negatively correlated. From preexercise HRV indices, only Poincaré plot parameters were correlated with T(on). No correlation between HRV indices and parameters of off-response was found. In conclusion, preexercise HRV parameters are not closely correlated with the rate of cardioacceleration at the onset of exercise and cannot predict the rate of HR recovery. On the other hand, postexercise HRV parameters are related to the rate of initial adjustment of HR to exercise referring to the importance of rapid HR on-response for a faster recovery after exercise.
在体育锻炼期间，心率（HR）通过副交感神经撤离和心脏交感神经活动增加而升高。时域和频域中的心率变异性（HRV）提供了有关心血管系统自主控制的信息。使用庞加莱图方法的非线性分析能够揭示有关心脏自主控制的补充信息。本研究的目的是确定HRV参数、运动开始时HR的初始升高（起始反应）与急性运动后恢复阶段HR降低（终止反应）之间的关联。对17名健康男性受试者（平均年龄：20.3±0.2（标准误）岁）在静息状态（仰卧25分钟；站立5分钟）、运动期间（以最大功率输出的70%进行8分钟台阶试验）和恢复阶段（仰卧30分钟）进行连续心率监测。对HR时间序列的选定片段进行时域和频域的HRV分析以及庞加莱图测量（长度、宽度）的评估。使用指数曲线拟合技术对HR的起始和终止反应进行量化。计算代表运动起始和终止反应速率的时间常数T（起始）和T（终止）。运动后HRV指标与运动起始反应的时间常数 - T（起始） - 呈负相关。从运动前HRV指标来看，只有庞加莱图参数与T（起始）相关。未发现HRV指标与终止反应参数之间存在相关性。总之，运动前HRV参数与运动开始时的心率加速速率没有密切相关性，也无法预测HR恢复速率。另一方面，运动后HRV参数与运动时HR的初始调整速率相关，这表明快速的HR起始反应对于运动后更快恢复的重要性。
