Effect of Meditation on Heart Rate Variability

The dynamics of the autonomic nervous system, a prime factor for variation of heart rate is modulated by lifestyle factors like meditation and breathing exercises. The effect of meditation (dhyana)practiced by disciples of Ramakrishna Mission(RKM) on the heart rate variability is examined. The heart rate (HR)of a group of disciples of RKM is obtained from ECG signal recorded over a short time duration. Lagged Poincare plot of the heart rate(HR), the method of the principal component analysis, and the autocorrelation of HR fluctuations are used to analyze the HR. The variation of Poincare parameters (SD1),(SD2) and their ratio (SD12), with a lagged number, are non-linear and reveal a significant change with meditation. In particular, the magnitude of the slope and the curvature of(SD12) with lagged number increases after meditation. The meditation reduces the heart rate and increases the stroke volume. A strong correlation between slope and curvature of (SD12) is noted from the correlation matrix of multi-dimensional data set resulting from the Poincaré plot. The principal components (PC) of data resulting from pre-and post-meditation are well separated in PC-space. The entropy associated with R-wave fluctuations for all meditators is reduced after meditation. The auto-correlation of HR fluctuations exhibits a highly correlated pattern after meditation. The study suggests that meditation improves the heart rate dynamics and the 'calmness' of mind.