Non-Pharmacological Intervention for Chronic Pain in Veterans: A Pilot Study of Heart Rate Variability Biofeedback

Objective: Chronic  pain  is  an  emotionally  and  physically  debilitating  form  of  pain  that  activates  the  body’s  stress response and over time can result in lowered heart rate variability (HRV) power, which is associated with reduced resiliency and lower self-regulatory capacity. This pilot project was intended to determine the effectiveness  of  HRV  coherence  biofeedback  (HRVCB)  as  a  pain  and  stress  management  intervention  for  veterans  with  chronic  pain  and  to  estimate  the  effect  sizes.  It  was  hypothesized  that  HRVCB  will  increase  parasympathetic  activity  resulting  in  higher  HRV  coherence  measured  as  power  and  decrease  self-reported  pain  symptoms  in  chronic pain patients. Study design: Fourteen veterans receiving treatment for chronic pain were enrolled in the pre-post intervention study. They were randomly assigned, with 8 subjects enrolled in the treatment group and 6 in the control group. The  treatment  group  received  biofeedback  intervention  plus  standard  care,  and  the  other  group  received  stan-dard care only. The treatment group received four HRVCB training sessions as the intervention. Measures: Pre-post  measurements  of  HRV  amplitude,  HRV  power  spectrum  variables,  cardiac  coherence,  and  self-ratings of perceived pain, stress, negative emotions, and physical activity limitation were made for both treat-ment and control groups.Results: The mean pain severity for all subjects at baseline, using the self-scored Brief Pain Inventory (BPI), was 26.71 (SD=4.46; range=21-35) indicating a moderate to severe perceived pain level across the study subjects. There was no significant  difference  between  the  treatment  and  control  groups  at  baseline  on  any  of  the  measures.  Post-HRVCB,  the treatment group was significantly higher on coherence (P=.01) and lower (P=.02) on pain ratings than the con-trol group. The treatment group showed marked and statistically significant (1-tailed) increases over the baseline in coherence ratio (191%, P=.04) and marked, significant (1-tailed) reduction in pain ratings (36%, P<.001), stress per-ception  (16%,  P=.02),  negative  emotions  (49%,  P<.001),  and  physical  activity  limitation  (42%,  P<.001).  Significant  between-group effects on all measures were found when pre-training values were used as covariates.Conclusions:  HRVCB  intervention  was  effective  in  increasing  HRV  coherence  measured  as  power  in  the  upper  range  of  the  LF  band  and  reduced  perceived  pain,  stress,  negative  emotions,  and  physical  activity  limitation  in  veterans suffering from chronic pain. HRVCB shows promise as an effective non-pharmacological intervention to support standard treatments for chronic pain.

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