Background: Psychiatric patients with adverse childhood experiences (ACE) tend to have dysfunctions in the interoceptive part of their emotional experience. The integration of interoceptive emotional activity in the insular and cingulate cortices is linked to the regulation of sympathovagal balance. This makes heart rate variability (HRV) an ideal measure for providing feedback on emotion regulation in real-time. Methods: A sample of one hundred (n=100) outpatients was evaluated. Participants underwent eight 30-minutes ACE exposure sessions during which patients were guided to experience bodily sensations related to ACE while their HRV was monitored using a commercial biofeedback device. Results: Comparing the results of the first to last therapeutic session, a significant decrease in heart rate and an increase in HRV at the onset of the session were observed. Conclusions: This study suggests a physiological impact of therapeutic interventions on autonomic balance and underlines the interest in HRV biofeedback as clinical practice.