Heart rate variability as a measure of autonomic nervous system function in anorexia nervosa.

ABSTRACT BACKGROUND AND HYPOTHESIS: Alteration in sympathovagal balance may be a mechanism of increased cardiovascular mortality and sudden death of patients with anorexia nervosa. This study was undertaken to characterize cardiac autonomic control in patients with anorexia nervosa by means of heart rate variability analysis. METHODS: Heart period variability by 24-h Holter recording was evaluated in 13 young women with anorexia nervosa, 10 constitutionally thin women, and 10 women of normal weight. RESULTS: High-frequency power, a measure of parasympathetic modulation of heart rate, and all-time domain measures of heart rate variability were higher in patients with anorexia nervosa than in thin women and in those of normal weight. Thin women showed lower values of total power and of most components of power spectrum. CONCLUSIONS: Our data demonstrate an increased vagal tone in young women with anorexia nervosa. The marked increase in parasympathetic activity, not in response to an increase in sympathetic activity, could be detrimental and may contribute to the higher cardiovascular mortality of these patients.