title: Impact of short-term practice of yoga on heart rate variability.
abstract: BACKGROUND
  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).
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Autonomic balance tilts toward parasympathetic predominance after 1 month practice of yoga.
authors: Department of Physiology, PES Institute of Medical Science and Research, Kuppam, Andhra Pradesh, India.
authors: A V
authors: AV
authors: Vinay
authors: Department of Physiology, M. S. Ramaiah Medical College, Bengaluru, Karnataka, India.
authors: D
authors: D
authors: Venkatesh
authors: Department of Physiology, M. S. Ramaiah Medical College, Bengaluru, Karnataka, India.
authors: V
authors: V
authors: Ambarish
keywords: Autonomic function; heart rate variability; yoga