The present paper concerns a new description of changing in metabolism during incremental exercises test that permit an individually tailored program of exercises for obese subjects. We analyzed heart rate variability from RR interval time series (tachogram) with an alternative approach, the recurrence quantification analysis, that allows a description of a time series in terms of its dynamic structure and is able to identify the phase transitions. A transition in cardiac signal dynamics was detected and it perfectly reflects the aerobic threshold, as identified by gas exchange during an incremental exercise test, revealing the coupling from the respiratory system toward the heart. Moreover, our analysis shows that, in the recurrence plot of RR interval, it is possible to identify a specific pattern that allows to identify phase transitions between different dynamic regimes. The perfect match of the occurrence of the phase transitions with changes observed in the VO₂ consumption, the gold standard approach to estimate thresholds, strongly supports the possibility of using our analysis of RR interval to detect metabolic threshold. In conclusion, we propose a novel nonlinear data analysis method that allows for an easy and personalized detection of thresholds both from professional and even from low-cost wearable devices, without the need of expensive gas analyzers.

中文翻译：

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肥胖受试者连续递增运动测试期间心率变异性的定量分析

本文涉及在增量运动测试中新陈代谢变化的新描述，该测试允许针对肥胖对象的运动进行个性化定制。我们使用另一种方法，即循环量化分析，从RR间隔时间序列（行进图）分析了心率变异性，该方法可以根据时间序列的动态结构来描述时间序列，并能够识别相变。检测到心脏信号动力学的变化，它完美地反映了有氧阈值，这是在递增运动测试中通过气体交换确定的，表明了从呼吸系统到心脏的耦合。此外，我们的分析表明，在RR间隔的重复图中，可以确定一种特定的模式，该模式可以识别不同动态范围之间的相变。相变的发生与VO _2中观察到的变化的完美匹配消费，估计阈值的金标准方法，强烈支持使用我们对RR间隔的分析来检测代谢阈值的可能性。总而言之，我们提出了一种新颖的非线性数据分析方法，可从专业甚至低成本的可穿戴设备轻松，个性化地检测阈值，而无需昂贵的气体分析仪。