使用改进Welch法估计心率变异功率谱分析人体疲劳程度

Estimation of the Power Spectrum of Heart Rate Variability Using Improved Welch Method to Analyze the Degree of Fatigue

心率变异性(HRV)是现代医学中判定人体状态的重要指标,本文采用改进的Welch方法分析HRV的频域特性,研究人体疲劳度与迷走神经的关系。本文首先给待处理信号加一个时间窗函数,根据需求设定时间长度之后再进行信号频域分析。此方法与经典谱分析方法中的周期图法相比,谱估计的分辨率和方差均得到改善,并且可以任意设定分析HRV的时间长度(目前测量短时HRV的国际标准是5min)。依照本文方法以PhysioNet提供的心电数据库分析疲劳人群的HRV特点,结果显示以Welch法结合适当的窗函数对HRV分析的准确度大大提高,并得到疲劳人群迷走神经活性下降、交感神经活性增强的结果。

Heart rate variability（HRV）is an important point to judge a person＇s state in modern medicine.This paper is aimed to research a person＇s fatigue level connected with vagal nerve based on the HRV using the improved Welch method.The process of this method is that it firstly uses a time window function on the signal to be processed,then sets the length of time according to the requirement,and finally makes frequency domain analysis.Compared with classical periodogram method,the variance and consistency of the present method have been improved.We can set time span freely using this method（at present,the time of international standard to measure HRV is 5minutes）.This paper analyses the HRV＇s characteristics of fatigue crowd based on the database provided by PhysioNet.We therefore draw the conclusion that the accuracy of Welch analyzing HRV combining with appropriate window function has been improved enormously,and when the person changes to fatigue,the vagal activity is diminished and sympathetic activity is raised.