The Effects of Heart Rate Variability Biofeedback on Functional Gastrointestinal Disorders: A Scoping Review

Functional Gastrointestinal Disorders (FGID) are a group of symptom-based disorders that occur across the alimentary tract and have a high prevalence globally in both adults and children. These symptoms are chronic and/or recurrent and often have substantial effects on quality of life. Their incidence is tied to multiple factors, including gut-brain axis imbalance, which includes autonomic dysregulation related to a relative withdrawal of vagal activity. Heart rate variability biofeedback (HRVB) is a non-invasive intervention that can influence autonomic activity and has shown benefit for diverse conditions including depression and anxiety, however the evidence of its effect has not yet been systematically assessed in FGIDs. This scoping review aimed to collate and evaluate the available literature regarding HRVB and FGIDs. We systematically searched four medical databases. Four articles met inclusion criteria for being interventional studies using HRVB in FGIDs. These were heterogeneous, including both paediatric and adult as well different subtypes of FGID. Two of the four studies demonstrated significant improvements from HRVB interventions in FGID symptoms while the other two found no significant difference. Scoping evaluation indicated this inconsistency likely reflects heterogeneous populations and study designs. Further scoping review of the broader HRVB literature also discovered that at least six weeks of HRVB is required to observe an impact on FGID symptoms and defined recommended guidance for performing future evaluations of HRVB in FGIDs. Evidence on HRVB for FGID is emergent, however HRVB appears a promising intervention when administered optimally. Further studies using best-practice techniques are required.