Changes In Heart Rate Variability After Cyclic Meditation Practice In Working Women

Submitted by Nidhi Choudhary
In partial fulfillment of The Master's degree in yogic sciences M.Sc. (Yoga)
To
Swami Vivekananda Yoga Anusandhana Samsthana, Bangalore

Abstract: Cyclic meditation (CM) is a yoga based stress management technique in which physical postures are interspersed with relaxation. CM is based on a statement in ancient yoga texts which suggests that combination of both 'calming' and 'stimulating' measures may be especially helpful in reaching a state of mental equilibrium. Changes in heart rate variability in working women were studied after CM. Of the 90 healthy female bank employees who were screened, 60 satisfied the inclusion/exclusion criteria and were selected after obtaining informed consent. Their age ranged from 25 to 50 years. They were randomly allocated to CM (30 subjects, age-mean ± SD =43.78±5.203 yrs) and control (30 subjects, age- mean±SD = 45.04±4.398 yrs) groups. CM practice was taught to the study group for 15 days, 25 minutes every afternoon during their working hours. The control group was given stress counseling. Assessment of heart rate variability (HRV) was made on 1st and 15th day for both the groups. The results showed that the two groups were matched for age but differed significantly on values for HRV. The normalized values for high frequency (0.15-0.50 Hz) component of the power spectrum of HRV increased (11%) and that of low frequency component (0.05-0.15 Hz) and LF/HF ratio reduced (12%), significantly after Cyclic Meditation (p=.001, Wilcoxon signed ranks test). Reverse trend of changes with decrease in HF (P<.001) and increase in (LF) and LF/HF ratio (P< .001) were observed in control group. ANCOVA showed significant interaction between subjects factors (p<.05) on all three HRV variables. The changes suggested decreased sympathetic arousal and increased cardiac vagal activity during CM indicating physiological rest following CM.

Summary & Conclusion: In the present study a significant decrease in LF power, LF/HF ratio and HR were observed with a significant increase in the HF power after the practice of CM. However in control group there was a significant increase in LF power and LF/HF ratio with a significant decrease in HF power and non significant decrease in heart rate. There was a significant difference between CM and control groups in all the three HRV variables.

The LF band of HRV is known to correspond to sympathetic modulations and the efferent vegal activity is a major contributor to the HF band. The LF/HF ratio is correlated with the sympatho-vagal balance.

The results of this study with reduction in physiological arousal after the practice of cyclic meditation (through HRV) are similar to our earlier study at this institution on CM in healthy male executives which showed reduction in respiratory rate and oxygen consumption immediately after the practice of CM (Telles, Reddy & Nagendra 2000).

A decrease in heart rate after the practice of CM also indicates a rested state similar to earlier observations on changes in heart rate during other yogic practices (Telles, et al., 2004). It has also been observed that after exercise the heart rate and blood pressure returned to the baseline levels sooner when subjects practiced guided relaxation compared with recovery after supine rest (Bera, Gore & Oak, 1998).

A study conducted to examine the independent and joint effects of occupational status and perceived demands, control and social support at work on ambulatory blood pressure and heart rate (HR) in women showed that occupational status and job characteristics accounted for 18% and 22% of the inter-individual variability in ambulatory systolic blood pressure (SBP) and HR respectively indicating high cardiovascular risk for women in stressful job circumstances (Gallo et al., 2004).There are no published studies on stress management through meditation or relaxation therapies in working women. Hence this practically feasible technique of CM (25 mins) which can be done in the office atmosphere could be recommended as a useful modality at work place.

Although care was taken in this study not to carry out the assessments during the menstrual period, different phases of menstrual cycle may have contributed to the differences in baseline HRV spectrum which was not matched between the CM and C groups.

Thus this randomized wait list control study has shown a significant decrease in sympathetic arousal and increase in vagal tone after the practice of Cyclic meditation for 25 mins daily for 15 days in female bank employees as compared to the control group. These results need to be substantiated by further studies on the effect of CM on other autonomic variables and correlations with other measures of stress.