Interoceptive mechanisms of a mobile heart rate variability biofeedback app for eating disorder symptoms: Proof-of-concept findings

Introduction: Recent US-based datasets (Ns > 1000) show over 1-in-4 adults suffer from clinically significant eating disorder (ED) symptoms. Methods for preventing subthreshold problems from becoming full-threshold EDs are needed. An 8-week, single-arm feasibility study of a mobile heart rate variability biofeedback (HRVB) app supported strong acceptability and preliminary efficacy for reducing ED symptoms. The present study investigated potential mechanisms of change from pre- to post-intervention. Method: Participants were 24 healthcare workers recruited during the COVID-19 pandemic who scored in the clinically significant range on the Loss of Control Eating Scale-Brief (LOCES-Brief) (92 % female, 83 % non-Hispanic white, Mean age = 42; SD = 11.8). Measures included the eight subscales from the Multidimensional Assessment of Interoceptive Awareness-2 (MAIA-2) for interoceptive sensibility, and the Eating Disorder Examination-Questionnaire 7-item Short (EDE-Q7) and LOCES-Brief for ED symptoms. Mediation analyses were conducted using the MEMORE macro for repeated measures, with indirect effects evaluated via 95 % Monte Carlo confidence intervals. Results: Significant indirect effects on EDE-Q7 scores were found for MAIA-2 ‘noticing’, ‘attention-regulation’, ‘emotional-awareness’, ‘self-regulation’, and ‘body-listening’ subscales. ‘Not-worrying’, ‘not-distracting’, and ‘trusting’ did not significantly mediate EDE-Q7 changes. For LOCES-Brief, significant indirect effects were found for ‘trusting’. No other MAIA-2 subscales showed statistically significant indirect effects for LOCES-Brief. Conclusion: Findings suggest HRV biofeedback may reduce ED symptoms by enhancing interoceptive skills. These results support further investigation into biofeedback as a low-cost, scalable intervention for populations at risk for EDs. Future studies should evaluate fully powered controlled efficacy trials of mobile HRVB as a preventive strategy for eating and body-related mental health concerns.