Background: Heart rate variability (HRV) is an established method to evaluate sympatho-vagal balance. Reduced HRV is a prognostic marker for fatal arrhythmias and increased mortality. Mindfulness based stress reduction (MBSR) is a well-delineated 8-week meditation program. Certain meditation practices have been shown to positively influence HRV, but the short- and long-term effects of MBSR on HRV have not been established.

Objective. It is to study the different effects of meditation and controlled breathing on HRV.

Methods: Twenty healthy volunteers were recruited from participants of a MBSR program. Continuous ECG and respiration were recorded in three phases (Resting, Controlled breathing, Meditation), with each phase lasting for 5 minutes, before and after completion of MBSR.

Time domain analysis was undertaken using standard deviation of RR intervals (SDNN) and root mean square of successive differences in adjacent RR intervals (RMSSD).

Results: After 8 weeks of MBSR, during meditation, there was no significant change in SDNN (50.9 ± 22.7 to 45.1 ± 20.7 ms, P=0.19) or RMSSD (35.0 ± 24.6 to 25.6 ± 13.1 ms, P=0.1). Compared to resting spontaneous breathing, controlled breathing was associated with significant changes in SDNN (36.9 ± 17.1 to 60.5 ± 20.4 ms, P<0.0001) and RMSSD (25.8 ± 12.6 to 34.1 ± 16.0 ms, P=0.013). Compared to meditation, controlled breathing also was associated with significant changes in SDNN (45.1 ± 20.7 to 60.5 ± 20.4 ms, P=0.001) and RMSSD (25.6 ± 13.1 to 34.1 ± 16.0 ms, P=0.0009).

Conclusion: Participation in a MBSR program did not lead to significant changes in time domain measures of HRV, either at rest or during meditation. However, controlled breathing at 6 breaths/minute produced significant improvement in HRV, compared to either resting spontaneous breathing or meditation. Although further study is warranted, controlled breathing could be a useful adjunct in management of conditions with reduced HRV, such as heart failure. (J Clin Prev Cardiol. 2014;3(1):1-4)

Keywords: autonomic nervous system; heart rate variability; MBSR; meditation; mindfulness

Volume 3, Number 1, Pages: 1-4

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