Modulating the Gut-Brain Axis: The Impact of HRV Biofeedback on IBS and Psychological Symptoms in Students

Disorders of the gut-brain interaction (DGBIs) are chronic gastrointestinal conditions characterised by the absence of identifiable structural or biochemical abnormalities. They affect approximately 40% of the global adult population and are frequently accompanied by psychological comorbidities, including anxiety and depression. DGBIs place a significant burden on individuals and healthcare systems, and patients often face stigma due to the lack of visible biological markers. The associations between DGBIs and psychological comorbidities share a common mechanism: an alteration in the autonomic nervous system (ANS), as reflected by reduced heart rate variability (HRV). Emerging research highlights HRV biofeedback as a promising mind-body intervention that could offer therapeutic benefits. This thesis investigated the effects of HRV biofeedback in a preliminary sample of 16 university students reporting significant levels of IBS and anxiety symptoms. Participants completed five sessions of HRV biofeedback over ten days. A within-subject pre-post design was used to assess changes in gastrointestinal symptoms (measured by IBS-SSS), psychological distress (measured by DASS-21), interoceptive awareness (measured by BPQ-SF), and HRV indices. It was hypothesised that HRV biofeedback would increase HRV and improve psychological and gastrointestinal symptoms. Results revealed statistically significant reductions in IBS symptom severity and perceived stress following the intervention, alongside significant increases in body awareness and supradiaphragmatic reactivity. However, no significant changes were found in HRV metrics, anxiety and depressive symptoms. Exploratory analyses showed a positive correlation between higher RMSSD and anxiety and a marginal, non-significant negative correlation between changes in HF power and IBS symptom severity. These findings suggest that HRV biofeedback may offer therapeutic benefits for stress and gastrointestinal symptom management in DGBI populations. However, the effects on anxiety, depression, and HRV require further investigation. Future research should explore longer interventions, larger samples, and controlled designs to better evaluate the clinical utility of HRV biofeedback for DGBIs.