Physical and psychological factors influencing heart rate variability in anorexia nervosa

Objective: The aim of this study was to determine which physical and psychological factors influence the autonomic nervous system (ANS) of patients with anorexia nervosa (AN). Methods: The subjects were 14 AN patients and 12 healthy controls. Beat to beat heart rate variability recorded in a supine position with a controlled respiratory rate of 15/min, was analyzed using power spectral analysis. Symptoms of anxiety and depression were assessed by State and Trait Anxiety Inventory and Zung's Self-rating Depression Scale respectively. Results: Anxiety had a significant negative correlation with the ANS of AN patients. The illness duration times body mass index (BMI), a measure of sustained extreme loss of weight, was also significantly associated with changes in the ANS of AN patients. Conclusion: Although the ANS is influenced by various factors, sustained extreme loss of weight seems to be more influential factor in AN patients.