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.

Background/objective: Several articles have described body composition in anorexia nervosa, whereas little is known about this issue in underweight ballet dancers and constitutionally lean females. The main aim of this study was to assess whether phase angle (a bioimpedance variable related to body cell mass) differs according to the type of underweight in female adolescents and young women. Subjects/methods: Skinfold thicknesses and bioimpedance analysis (whole body and limbs) were evaluated in three groups of underweight patients (30 patients with anorexia nervosa, 10 constitutionally lean individuals and 15 classical dancers) and 30 normal weight controls. Results: There were no differences between the three groups of underweight patients with respect to anthropometric and bioelectrical impedance analysis (BIA) variables with the exception of phase angle. The latter was significantly higher in dancers, lower in anorectic patients and not different in constitutionally lean patients, as compared with controls. Conclusions: Phase angle (assessed by single-frequency BIA) appears to discriminate between different forms of underweight, being an effective marker of qualitative changes in body composition.

BAT activity has been shown in CL in resting thermoneutral conditions and may exert a role against adipose tissue deposition.

Background: The prevalence of anorexia nervosa among males is increasing but few data are available in the literature. This cross sectional study aims to evaluate resting energy expenditure (REE) and phase angle as a marker of qualitative changes of fat free mass (FFM) in three leanness groups as compared with control subjects. Methods: 17 anorectic (AN) males, 15 constitutionally lean (CL) individuals, 12 ballet dancers (DC), and 18 control (CTR) subjects were evaluated. REE was measured by indirect calorimetry (V max29- Sensormedics), and body composition was evaluated by bioimpedance analysis (BIA) at 50 kHz (DS Medica). Phase angle (a bioimpedance variable related to nutritional status) was used to evaluate differences in FFM characteristics between these three types of leanness. Results: REE, adjusted for FFM and fat mass (FM), were significantly higher in CL and lower in AN individuals (1783 ± 47 vs. 1291 ± 58 kcal, p < 0.05) compared to the other groups. Body composition was similar in AN and CL whereas dancers had the highest FFM (58.9 ± 4.8 kg, p < 0.05); anorectic males showed the lowest phase angle (5.8 ± 1.2 degrees vs. other groups, p < 0.05) and dancers the highest phase angle (7.9 ± 0.7 degree vs. other group, p < 0.05). Conclusions: Our findings confirm that phase angle could be a useful marker of qualitative changes, above all in the field of sport activities. On the other hand, there is the need to further evaluate the relationship between resting energy expenditure, body composition and endocrine status in different conditions of physical activity and dietary intake.

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