Multiscaled crucial events complexity analysis of heart rate signals during Tibetan singing bowls meditation

Investigating the effect of Tibetan Singing Bowls (TSB) meditation on physiological features including heart rate is limited. This study focused on applying multiscale modified diffusion entropy analysis (MSMDEA) on heart-rate fluctuations exhibiting $1 /$ f noise. MSMDEA identifies the contribution of crucial events within a $1 / \mathrm{f}$-noise time series that differs from the well-known Fractional Brownian Motion (FBM) 1/f-noise. Crucial events $(\mu)$ are defined as the waiting time distribution characterized by an inverse power law probability density function with the temporal complexity coefficient $\boldsymbol{\mu}$ at $2\lt \mu\lt3$ computed from the MSMDEA complexity scaling parameter $\delta$. Five healthy participants underwent a 50-minute session of TSB meditation with their heart rate signals measured using a Polar Ignite wristwatch. MSMDEA was applied across 20-time scales on the signals from the first ten minutes of the session as control compared to the TSB meditation of 40 minutes. Results indicate a shift to higher complexity for all scales in the TSB medication group ($\mathbf{p}\lt0.05$), suggesting that TSB has a strong influence on the sympathovagal balance associated with $1 / \mathbf{f}$-noise and consequently on stress and anxiety.