Figure 3.

The time course of heart-rate variability (HRV) changes are shown in relation to the onset of the 3 different movement types analyzed. Analysis was performed in the time domain (HRV) as well as in the time-frequency plane using a continuous wavelet transform (low frequency [LF], high frequency [HF], and LF/HF). Thick lines show mean ± SEM values. Stair plots below each graph indicate the statistical probability that HRV changes are equal for all 3 movement types at the given time point.

Note the 2 distinctive peaks of LF and HF power changes as well as of LF/HF ratio changes, occurring similarly for all examined movement types. LF-power- and LF/HF-ratio changes before and immediately after movement onset (indicating sympathetic activations, process 2) were significantly different between movement types. Furthermore, LF-power changes 4 seconds after movements (indicating vagal activations, process 3) were significantly different. PLMS refers to periodic limb movements of sleep; ILMS, isolated leg movements in sleep; RRLMS, respiratory-related leg movements in sleep.