Heart Rate Variability Interventions in Populations With Chronic Pain: A Scoping Review

Background and Purpose: Low heart rate variability (HRV) has been correlated with chronic pain, making it the target of behavioral and rehabilitation interventions. This scoping review aimed to synthesize the literature on nonpharmacological HRV interventions in populations with chronic pain. Methods: Following PRISMA guidelines for scoping reviews, the Pubmed, CINAHL Plus, MEDLINE, SPORTdiscus, and Academic Search Complete databases were searched. Experimental studies reporting quantitative HRV outcomes in adult populations with chronic pain were included. Data on study author, year, country, study design, population description (diagnosis, mean age), number and sex of participants, intervention, HRV and other measures, and HRV results were extracted from eligible studies. Results: Sixty-eight articles received full-text review, and 39 studies were included for data extraction. Of these, 46.2% were randomized controlled trials. The most common chronic pain diagnosis in the included studies was fibromyalgia (35.9%). The most common intervention was exercise (33.3%). Twenty-two interventions resulted in statistically significant increases in HRV. Those within the physical therapy scope of practice included aerobic exercise, thoracic mobilization, group exercise through exergames, warm water exercises, tai chi, HRV biofeedback, focused breathing, yoga, head and neck massage, myofascial release, and walking. Conclusion: This scoping review organizes the current literature on nonpharmacological HRV interventions in populations with chronic pain and offers an overview of evidence-based interventions. However, methodological heterogeneity such as disparate inclusion criteria and interventions precludes a robust comparative analysis. Future research should include more physical performance measures, randomized controlled trials, and larger sample sizes.