Positive Health Online

Abstract

VEMPATI and TELLES, Swami Vivekananda Yoga Research Foundation, Chamarajpet, Bangalore, India, studied the effects of yoga-based guided relaxation compared with simply lying down and resting on sympathetic nervous system activity in adult males.

Background

Methodology

This study involved 35 healthy men aged 20-46 years. The subjects underwent two types of relaxation: 1) yoga-based guided relaxation and 2) rest lying down. Measures of autonomic nervous system activity (including heart rate by ECG and skin conductance by galvanic skin response), oxygen consumption and volume of air breathed were monitored.

Results

Assessments of autonomic indicators were completed for 15 subjects and those for oxygen consumption and breath volume for 25 subjects. Oxygen consumption decreased significantly and breath volume increased significantly after guided relaxation. The two types of relaxation produced similar reductions in heart rate and skin conductance. During guided relaxation, there was a reduction in the power of the low frequency (LF) component of the heart rate variability spectrum and an increase in the power of the high frequency (HF) component, which suggested a reduction in sympathetic nervous system activity. Further analysis revealed that subjects who had a baseline ratio of LF/HF greater than 0.5 demonstrated a significant reduction in the ratio after guided relaxation; whereas, subjects with a baseline ratio less than or equal to 0.5 did not show this change.

Conclusion

Yoga-based guided relaxation decreased sympathetic nervous system activity depending on subjects’ baseline levels.

References

Vempati RP, Telles S. Yoga-based guided relaxation reduces sympathetic activity judged from baseline levels. Psychological Reports 90 (2): 487-94. Apr 2002.