Title: Evaluation of heart rate dynamics during meditation using Poincaré phase plane symbolic measures
Authors: Chandrakar Kamath
Addresses: ShanthaNilaya, 107, First stage, Ananthnagar, Manipal, 576104, India
Abstract: Meditation has long been known to affect human physiology which is mediated through autonomic nervous system. The main objective of this study was to assess dynamic changes in cardiac inter-beat intervals and autonomic nervous system during meditation hypothesising that Poincaré plots in conjunction with symbolic dynamics can lead to better understanding of the dynamics of the underlying physiological mechanisms. The Poincaré phase plane standard descriptors can measure only linear gross variability of the heart rate time series. Moreover, these descriptors exhibit limitations where the occurrence of nonlinear behaviour may be responsible to distinguish the phase plane patterns. We captured the changes in Poincaré phase plane patterns resulting from nonlinear processes, during two meditation techniques, employing two complexity measures, symbolic dynamics entropy and forbidden words, which are appropriate to distinguish between the two states. Findings show that symbolic dynamics entropy, also a marker of parasympathetic activity, reveals that during premeditation state, there is parasympathetic dominance while during meditation state there is sympathetic dominance in both the meditation techniques. We also show the presence of nonlinear deterministic structures in the meditation inter-beat interval time series and appropriateness of the application of our nonlinear approach through surrogate data analysis.
Keywords: forbidden words; heart rate variability; HRV; meditation; Poincaré phase plane; PPP; RR interval time series; symbolic complexity measures; symbolic dynamic entropy; SDEn.
International Journal of Biomedical Engineering and Technology, 2019 Vol.29 No.4, pp.385 - 402
Received: 26 Aug 2016
Accepted: 28 Nov 2016
Published online: 20 Jun 2019 *