Electrocardiogram signals for fatigue analyses of marathon runners

In order to study the regularity of ECG changes of marathon runners during half-marathon, we collected the ECG data of 20 male marathon runners during exercise, and analyzed the time domain, frequency domain and nonlinear characteristics of ECG signal heart rate variability. The results show that with the increase of movement distance, the time domain indexes MEAN and SDNN decrease significantly; the frequency domain indexes LF and LF/HF increase significantly, and the HF index decreases significantly; the nonlinear indexes approximate entropy and sample entropy decrease significantly. The index values before and after exercise were significantly different, and different exercise fatigue states could be distinguished by the changes in index values. Marathon athletes have good physiological adaptability after long-term low-intensity or short-term high-intensity training, especially the parasympathetic nerve has a high tension in the resting state. Heart rate variability can represent the time domain parameters of parasympathetic nerve tension and changes, and is an important parameter for judging the physical energy reserve of body fatigue and exercise. (Abstract)