The effects of integral yoga nidra on autonomic cardiac control
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Abstract
Yoga has become a popular form of exercise offered in group fitness programs at most health clubs in the U.S. The very old, traditional practices of yoga are intended to unite the body, mind and spirit, teach self control, and bring freedom from disease. Especially emphasized in the traditional form is a relaxation technique called yoga nidra. Yoga nidra produces a relaxation response that is meant to have lasting positive effects. When the body functions in a relaxed state, the parasympathetic branch of the autonomic nervous system is dominant, creating a foundation for healthy systems in the body, including a healthy heart. The heart functions under the influence of the autonomic nervous system for the maintenance of homeostasis (Brouha & Nowak, 1939). In a normal, healthy person interbeat intervals fluctuate, and the magnitude of fluctuation is associated with autonomic efferent traffic. These interbeat
intervals, or heart rate variability (HRV), are determined by measuring the distance between the R-R intervals on an electrocardiogram (ECG) recording. PURPOSE: To test the hypothesis that an eight week program of Integral Yoga Nidra will effectively improve HRV in older adults. METHODS: HRV was measured in eleven older adults (age 78 ± 7 yrs; height 150 ± 38 cm;
weight 46 ± 45 kg; mean ± SE) by ECG during controlled respiration (15 breaths/min). Subjects then participated in an eight-week relaxation program (Integral Yoga Nidra) three days per week, followed by a second HRV assessment. RESULTS: As a group, RRI LF t(10) = 0.997, (p = 0.342), RRIHF t(10) = 0.955 (p = 0.362), RRI t(10) = 0.203, (p = 0.844), pNN50 t(10) = 0.930
(p = 0.374 ), and RRI standard deviation t(10) = 0.669, (p = 0.052) were not significantly increased following yoga training. CONCLUSIONS: These findings demonstrate that yoga nidra training in our cohort of older adults, did not result in a chronic increase in parasympathetic predominance as assessed from analysis of heart rate variability.