Vipassana Meditation Practices Enhance the Parasympathetic Activity during Sleep: a Case-Control Study of Heart Rate Variability across Sleep Cycles

1.1.Background:Sleep state related cardiac autonomic modulations are important for proper cardiovascular functions and to maintain homeostasis during sleep. The present study evaluates the efficacy of Vipassana meditation on cardio autonomic dynamicity across sleep cycles during sleep. 1.2.Methods:26 Senior Vipassana meditation practitioners and 23 non-meditating control subjects participated in the study. Whole night polysomnography with lead II ECG were carried out using 32 channel, 2110 digital EEG system (Nihon Kohden, Japan) and with 16 channels Power Lab data acquisition system (AD Instruments, Australia . Differences in sleep variables across sleep cycles among the meditation practitioners and control groups (between groups ) were analyzed by two way ANOVA with turkey posthoc test .The heart rate variability (HRV) was assessed during N2 and N3 and REM sleep state across three consecutive sleep cycles. The HRV variables-High frequency power (HF) and low frequency power (LF) density, their normalized units (HFnu and LFnu) and ratio (LF/HF ratio) were compared across sleep cycles using Analysis of variance with repeated measures for within group and ‘t’ test for between groups. 1.3.Results:Vipassana meditators showed significantly high HFnu irrespective of sleep states across sleep cycles. During REM sleep, as HF nu was concomitantly enhanced along with increased LFnu, the LF/HF ratio was reduced in meditators .In addition, meditators showed distinct sleep architecture with enhanced slow wave sleep and REM sleep states along with significantly reduced intermittent awakenings indicative of proper sleep organisation. 1.4.Conclusion: Vipassana meditation practice helps to establish a proper cardio autonomic dynamicity during sleep with a persistent increase in parasympathetic activity across sleep states. Such a state of heightened parasympathetic activity especially during REM sleep helps to buffer the sympathetic surges and helps to maintain a proper sympatho-vagal balance essential for quality sleep and cardio protection.