Does the Temporal Asymmetry of Short-Term Heart Rate Variability Change during Regular Walking? A Pilot Study of Healthy Young Subjects

Figure 1

Wavelet-based nonstationary trend removal procedure. (A) The original RR interval time series. (B) The RR interval time series after the even resampling. In order to clearly demonstrate the even resampling time points (red dots) and the original time points (black dots), a segment of data from (A) is zoomed in and shown in this panel. (C) The 6-level wavelet decomposition. (D) Trend with even sampling points is obtained from wavelet reconstruction of the approximate coefficients on the 6th level. (E) The actual nonstationary trend (purple) is obtained from the uneven recovering sampling from the trend component in panel (D). (F) The detrended RR interval time series is obtained by subtracting the actual nonstationary trend from the original RR interval time series.