Assessment of heart rate dynamic characteristics during meditation using symbolic dynamics analysis

Abstract

We present a computationally simple, but efficient method to: 1) estimate how far the symbolic dynamics analysis helps to characterise the nonlinear properties of RR interval time series during two concentration meditation techniques and thereby discriminate between pre-meditation and meditation states; 2) study the balance between the sympathetic and parasympathetic branches of the autonomic nervous system. The symbolic analysis calculations were performed on pre-meditation and meditation RR interval series. This analysis decomposes the series into patterns lasting three-consecutive time points (length-3 symbol sequences) and classifies them into four pattern families based on variability. Differences in these pattern families showed that sympathetic activation is increased during meditation state, while parasympathetic activation predominantly decreased, irrespective of the type of meditation. The entropies derived from the histograms of length-3 symbol sequences show that in both the meditation methods the complex dynamics of the RR interval series is lowered during meditation.