Just One Month of Yoga Decreases Stress Increases Heart Rate Variability

by Mike Mutzel


Researchers in India reported that just one month of yoga statistically significantly increased parasympathetic tone and heart rate variability (HRV) in over 30 subjects studied. 

Background on Heart Rate Variability

Reduced heart rate variability (HRV) is a strong predictor of cardiovascular disease, metabolic syndrome and inflammation and even all cause mortality. HRV is a non-invasive, yet a sensitive way to asse early stress-related changes in cardiovascular function.

Mind body-based therapies known to shift the body into a more parasympathetic balance and increase HRV include yoga, meditation, pranic breathing and guided imagery.

One of the easiest ways to assess your level of inflammation, metabolic control, and overall stress balance is through heart rate variability (HRV) assessment. Multiple studies have shown increased parasympathetic activity to be strongly linked with increased variability, or frequency, in the beating of the heart. In contrast, reduced heart rate variability is linked with inflammation (elevated c-reactive protein and white blood cells), metabolic dysfunction, cardiovascular disease, and an overall stress response.

Reduced heart rate variably (HRV) to strongly correlate with metabolic syndrome and inflammation and all cause mortality.

Study Details

40 male subjects were recruited to perform one hour sessions of yoga. Three bio markers of the cardiac cycle (i.e. which comprise the heart rate variability score) were measured prior to the intervention and were assessed after the 30 day yoga intervention.

Statistically significant increases were absorbed in all three biomarkers; suggesting increase functional ability of the heart and reduced sympathetic predominance in favor of parasympathetic predominance.

Summary and Conclusion

One month of yoga leads to significant increases in heart rate variability (HRV), a direct measurement of parasympathetic tone. Increased HRV is linked to improved emotional resilience and ability to cope with psychological stress.

This study builds on prior research reports indicated that reduces heart rate, blood pressure, blood viscosity, and cortisol levels, all of which reduce the risk of heart attack and stroke. Prior research reports that yoga also increases blood flow to the intestines.

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Study Abstract


Yoga is a science that facilitates homeostasis, an ancient way of life intended to improve the quality of life of an individual. Practice of yoga is proposed to alter the autonomic nervous system and affect the cardiovascular functioning. This study was intended to assess the influence of short-term practice of yoga for a month on heart rate variability (HRV).


Totally, 40 healthy male volunteers in the age group of 30-60 years willing to practice yoga for a month were included in the study. HRV was assessed using HRV device (RMS Vagus, India). Preinterventional assessment of HRV was done in these subjects. Practice of yoga that included a set of physical postures (asanas), breathing techniques (pranayama), and meditation (dhyana) were performed for an hour daily for 1 month under the guidance of a certified yoga instructor. Postinterventional assessment of HRV was done. The values were expressed in median and their interquartile range, and statistical analysis was done to compare the changes using Wilcoxon Signed Rank Test.


Thirty-two of 40 subjects recruited for yoga practice completed the study protocol. Analysis of HRV revealed that in time domain parameters, SDNN increased from 33.60 (31.41-44.82) to 42.11 (34.43-57.51), RMSSD increased from 22.00 (16.00-33.80) to 25.6 (17.0-34.8), and PNN50 increased from 2.45 (0.80-15.38) to 7.35 (1.40-18.57) after intervention. In the frequency domain parameters, the low-frequency (LF) power spectrum reduced from 39.30 (25.1-46.25) to 30.40 (22.75-40.62) and LF/high-frequency ratio was reduced from 2.62 (1.91-4.07) to 2.28 (1.4-3.07) after 1 month practice of yoga. P < 0.05 was considered statistically significant.


Autonomic balance tilts toward parasympathetic predominance after 1 month practice of yoga.


Vinay, AV. Int J Yoga. 2016  Impact of short-term practice of yoga on heart rate variability. Jan-Jun;9(1):62-6. doi: 10.4103/0973-6131.171714. 

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