Heart rate variability in chronic low back pain patients randomized to yoga or standard care

Background: Chronic pain can alter the autonomic balance with increased sympathetic activity reflected in altered heart rate variability (HRV). It has been proposed that yoga can be useful to correct the autonomic imbalance in patients with chronic pain who have reduced HRV. Methods and designs: In the present randomized controlled trial 62 patients with chronic low back pain associated with altered alignment of intervertebral discs (aged between 20 and 45 years, 32 males) were randomized to 2 groups. One group received yoga for 3 months while the other group carried out standard medical care based on the physician's advice. The duration was the same, i.e., 3 months. The heart rate variability and rate of respiration were assessed at baseline and at the end of 3 months. Results: There was a significant difference in the baseline (pre) values between groups (p = 0.008) for respiration rate which was higher in the yoga group. The changes reported below are pre-post comparisons within each group. The yoga group showed a significant (p < 0.05; repeated measures ANOVA, post-hoc analyses) decrease in the LF power of HRV, rate of respiration and a significant increase in the HF power of HRV and in the pNN50. Conclusion: The results suggest that yoga practice can shift the autonomic balance towards vagal dominance in patients with chronic low back pain associated with altered alignment of intervertebral discs.