Analysis of heart rate variability during meditation using sequential spectrum

This study examined the discriminative power of sequential spectrum analysis of the heart rate (HR) time series in separating pre-meditation and meditation states, thereby understand its effect on health. The HR time series was converted into a series of discretised binary symbols and the distribution of mono-sequences (i.e. tuples containing only one type of symbol '0' or '1') was computed. The relative distribution of mono-sequences containing only one type of symbol constitutes binary occupancy for that symbol in the sequential spectrum. The quantified Rényi entropies of the binary occupancies in the sequential spectra showed that meditation induces increased complexity in the heart rate. The sequential spectra showed that there was an increase in the binary occupancies of low frequency band and a decrease in the binary occupancies of high frequency band during meditation compared to those prior to meditation, reflecting a shift of frequency. These results significantly add to the meditation-cardiac health connection.