Fasten und (Über)-essen: Auswirkungen von Jojo-Diäten auf Parameter der kardialen sympatho-vagalen Balance

Background: Findings from animal studies suggest sympathetic inhibition during dietary restriction as opposed to increased sympathetic activity during re-feeding. Objective: The present study investigated sympatho-vagal balance in relation to endocrinological parameters of malnutrition status in women diagnosed with bulimia nervosa. Methods: Sixteen female volunteers diagnosed with bulimia nervosa were categorised according to their serum profile (glucose, pre-albumin, insuline-like growth factor, TSH, leptin) into currently malnourished (i.e. fasting) versus non-malnourished (not fasting) and compared with fourteen non-eating disordered controls matched for age and BMI. Spectral components of heart rate variability (HRV) were calculated on resting heart rate data using autoregressive analysis. Results: As expected, fasting bulimic women displayed lower values of resting heart rate compared to non-fasting women and controls. Non-fasting bulimic women consistently showed lower results in the vagally mediated component and significantly higher results in the sympathetically mediated component of HRV. Conclusions: These results confirm the notion of cardiac sympathetic inhibition during caloric restriction and increased activity during periods of normal eating or bingeing.