Enhanced dehydroepiandrosterone levels are positively correlated with N3 sleep stage in long-term mindfulness meditation practitioners.

Objectives: Meditation practices positively influence the neural, hormonal and autonomic systems. We have demonstrated that long-term practice of mindfulness meditation increases N3 and rapid eye movement (REM) sleep stages and bring efficient autonomic modulation during sleep. In the present study, the probable humoral correlation that could bring about these changes is evaluated. Material and Methods: Long-term Vipassana meditators (n=41) and controls (n=24) (males, 30-60 years of age) underwent a two-day consecutive whole night polysomnography recording. During the second day, with exposure to 100Lux brightness, blood was sampled from the antecubital vein between 8-9 PM and in subsequent early morning. Sleep stage was scored as per American Society of Sleep Medicine (ASSM) guidelines for the second-day recording. Sleep-related hormones were estimated - melatonin by radioimmunoassay; dehydroepiandrosterone (DHEA), cortisol, growth hormone (GH) and prolactin with enzyme-linked immunosorbent assay (ELISA); DHEA/cortisol ratio was calculated. Percentage of sleep stages and hormonal levels were compared between both groups using independent 't' test and Pearson's correlation was estimated between sleep stages and hormonal levels. Results: Meditators showed increased N3, REM sleep stages. Though evening cortisol was comparable between the two groups; early morning cortisol, diurnal DHEA and melatonin were significantly higher in meditators. Diurnal DHEA correlated significantly with the N3 sleep stage in meditators. Discussion: Higher diurnal DHEA despite variations in corresponding cortisol in meditators demonstrates that long-term Vipassana meditation practice modulates the hypothalamicpituitary-adrenal (HPA) axis and thereby influences sleep. Thus, the study provides evidence to explore the mechanism most likely involved with mindfulness meditation intervention in insomnia.

Senior Vipassana Meditation practitioners exhibit distinct REM sleep organization from that of novice meditators and healthy controls.

The present study is aimed to ascertain whether differences in meditation proficiency alter rapid eye movement sleep (REM sleep) as well as the overall sleep-organization. Whole-night polysomnography was carried out using 32-channel digital EEG system. 20 senior Vipassana meditators, 16 novice Vipassana meditators and 19 non-meditating control subjects participated in the study. The REM sleep characteristics were analyzed from the sleep-architecture of participants with a sleep efficiency index >85%. Senior meditators showed distinct changes in sleep-organization due to enhanced slow wave sleep and REM sleep, reduced number of intermittent awakenings and reduced duration of non-REM stage 2 sleep. The REM sleep-organization was significantly different in senior meditators with more number of REM episodes and increased duration of each episode, distinct changes in rapid eye movement activity (REMA) dynamics due to increased phasic and tonic activity and enhanced burst events (sharp and slow bursts) during the second and fourth REM episodes. No significant differences in REM sleep organization was observed between novice and control groups. Changes in REM sleep-organization among the senior practitioners of meditation could be attributed to the intense brain plasticity events associated with intense meditative practices on brain functions.

Meditation and its regulatory role on sleep.

Intense meditation practices help to achieve a harmony between body and mind. Meditation practices influence brain functions, induce various intrinsic neural plasticity events, modulate autonomic, metabolic, endocrine, and immune functions and thus mediate global regulatory changes in various behavioral states including sleep. This brief review focuses on the effect of meditation as a self regulatory phenomenon on sleep.