Correction

Following publication of the original article [1], the author reported these required corrections to Fig. 5 and Fig. 6:

Fig. 5:

The last graph of the first line, titled LF v, should be HFv

The last bottom graphs, titled SDnn and RR nn, should be HF (instead of SDnn) and LF/HF (instead of RRnn)

Fig. 6:

The title of the last graph bottom line is LF/HF (instead of HF/LF).

The original article [1] has been updated to reflect this.