Analysis of the variations of heart activity during different human activities is an important area of research in sport sciences. Therefore, in this paper, we evaluated the variations of heart activity for 23 subjects while sitting, hand biking, walking, and running. Since the obtained R-R time series (as the indicator of heart rate variability (HRV)) has a complex structure that contains information, we employed fractal dimension, sample entropy, and Shannon entropy for our analysis. According to the results, doing a harder activity causes a more significant alteration in the complexity and information content of HRV. The results of statistical analyses also verified the obtained results. Similar investigations can be conducted in case of other activities to evaluate the variations in heart activity in different conditions.

中文翻译：

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坐着、手骑自行车、步行和跑步时心率变异性 (HRV) 的复杂性和基于信息的分析

分析不同人类活动中心脏活动的变化是运动科学研究的一个重要领域。因此，在本文中，我们评估了 23 名受试者在坐着、骑自行车、步行和跑步时的心脏活动变化。由于获得的 RR 时间序列（作为心率变异性 (HRV) 的指标）具有包含信息的复杂结构，因此我们采用分形维数、样本熵和香农熵进行分析。根据结果​​，进行更艰苦的活动会导致 HRV 的复杂性和信息内容发生更显着的变化。统计分析结果也验证了所得结果。在其他活动的情况下可以进行类似的调查，以评估不同条件下心脏活动的变化。