Loving-kindness meditation's effects on nitric oxide and perceived well-being: a pilot study in experienced and inexperienced meditators.

Background: Meditation is associated with lower blood pressure, but little is known about how loving-kindness meditation affects nitric oxide (NO) metabolism, a key mediator of cardiovascular physiology associated with vasodilation.

Methods: We studied seven inexperienced and five experienced healthy meditators at one study visit, after they refrained from eating nitrate-rich foods for at least 12h. Participants completed questionnaires on demographics and meditation practices. We measured nitrite and nitrate and self-reported stress at baseline, after a neutral reading period (prior to meditation), immediately after, and 10 min following a standardized 20-min loving-kindness meditation.

Results: The 12 subjects had a mean age of 51 years, and two were male. Stress was significantly lower at baseline in the experienced group (15 vs. 49 on 100 point scale, P < .05) as was heart rate (HR) [68.1 ± 0.5 beats per minute (bpm) vs. 73.4 ± 0.7 bpm, P < .05]. Stress levels fell significantly with meditation (52 vs. 11, P < .05), while relaxation increased (55 vs. 89, P < .05) in the inexperienced group. Plasma nitrite levels were not significantly higher, but nitrate levels were more than twice as high (P < .05) for experienced vs. inexperienced meditators before and after loving-kindness meditation.

Conclusion: Loving-kindness meditation is associated with stress reduction in inexperienced meditators. Experienced meditators had higher nitrate levels, trended toward having higher nitrite levels, and had significantly lower stress levels than inexperienced meditators. Nitric oxide metabolism may be involved in the cardiovascular effects of persistent meditation practice. Larger longitudinal studies would be fruitful to better understand the mechanisms involved.