Purpose: The main aim of this paper is to study the influence of temperature on multiscale entropy (MSE) and multiscale time irreversibility (MTI) through the use of short-term measurements. Methods: A total of 12 physically active, healthy, and nonsmoker individuals ([Formula: see text] years old; [Formula: see text][Formula: see text]cm of height; and [Formula: see text][Formula: see text]kg of body mass) voluntarily participated in this study. Two beat-to-beat recordings of 15[Formula: see text]min length were performed on every participant, one under hot conditions ([Formula: see text]C) and the other assessment under cool conditions ([Formula: see text]C). The order of these two assessments was randomly assigned. Multiscale sample entropy and MTI were assessed in every measurement through 10 scales. Results: Entropy was significantly higher under hot conditions ([Formula: see text]) from the fifth scale compared to cool conditions. On the contrary, MTI values were significantly lower under hotter conditions ([Formula: see text]). Conclusions: The study of MSE and time irreversibility of short RR measurements presents consistent and reliable data. Moreover, exposures to hot conditions provoke an increment of interbeat complexity throughout larger scales and a decrease in the MTI in a healthy population.

中文翻译：

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基于环境温度的RR时间序列的多尺度熵和多尺度时间不可逆性分析

目的：本文的主要目的是通过使用短期测量来研究温度对多尺度熵（MSE）和多尺度时间不可逆性（MTI）的影响。方法：共12名体力活动、健康、不吸烟的个体（[公式：见文]岁；[公式：见文][公式：见文]身高；[公式：见文][公式：见正文]kg 体重）自愿参加了这项研究。对每位参与者进行两次 15[公式：见文本]分钟的逐搏记录，一个在高温条件下（[公式：见文本]C），另一个在凉爽条件下进行评估（[公式：见文本] C）。这两个评估的顺序是随机分配的。通过 10 个尺度在每次测量中评估多尺度样本熵和 MTI。结果：与冷条件相比，从第五尺度开始，热条件下（[公式：见文本]）的熵显着更高。相反，在较热的条件下，MTI 值显着降低（[公式：见正文]）。结论：对 MSE 和短 RR 测量的时间不可逆性的研究提供了一致和可靠的数据。此外，暴露在高温条件下会在更大范围内引起节拍间复杂性的增加，以及健康人群中 MTI 的降低。