SampEn shows no significant change during exercise. Sample Entropy (SampEn) and slope of Detrended Fluctuation Analysis (DFA α1) were measured during the whole session.ĭFA α1 declines with exercise, being less in the VT1 trial than in the other two. The duration of VT1 and VT2 loads were selected in such a way that the product intensity-duration (training load) was the same. Each subject ran at VT1 and VT2 speeds and MAS (second, third and fourth day). The first session was an incremental treadmill test to determine ventilatory thresholds (VT1 and VT2) and maximal aerobic speed (MAS). We aimed to analyse the complexity and fractal nature of heartbeat during constant exercise, at three different intensities, and recovery.įourteen healthy men underwent 4 separate sessions. We suggest that the complexity in heart rhythm is achieved through coupling between intrinsically controlled heart rhythm and autonomic control, and that the model of stochastic resonance mechanism could be applied to this system. The difference between scaling exponents disappeared in a state of efficient autonomic control. With an increase in RR interval, accompanied by increased variability (increase in parasympathetic control), the difference between αĢ decreases. In this case, DFA reveals a white noise over short scales (αġ about 0.5) and strongly correlated noise over large scales (αĢ about 1.5). At the shortest RR intervals, which correspond to extreme physiological and pathological conditions, we found the highest reduction of variability and the biggest difference between scaling exponents. We found that the difference between αĢ is related to RR interval length. In addition, we calculated standard deviation of RR intervals (SDRR) as the simplest variability measure. Using detrended fluctuation analysis (DFA) method we determined short-term (αĢ) scaling exponent. In this study, we investigate correlation properties of fluctuations in heart interbeat (RR) time series in a broad range of physiological and pathological conditions.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |