High levels of physical activity in female adolescents with anorexia nervosa: medical and psychopathological correlates

PURPOSE: While overexercise is commonly described in patients who experience anorexia nervosa (AN), it represents a condition still underestimated, especially in the paediatric population.METHOD: The present study aims at assessing the possible associations between levels of physical activity (PA) and clinical features, endocrinological data and psychopathological traits in a sample of 244 female adolescents hospitalised for AN subdivided into two groups according to PA levels (high PA vs. no/low PA). The two groups were compared through multivariate analyses, while multiple regression analysis was conducted to determine whether physical activity predict specific outcomes.RESULTS: No significant differences were found between the two groups in terms of last Body Mass Index (BMI) before illness, BMI at admission and disease duration, while a difference emerged in delta BMI(rapidity of weight loss), significantly higher in high-PA group (p=0.021). Significant differences were observed in Free triiodothyronine- (p<0.001), Free thyroxine (p=0.046), Follicle-stimulating hormone (p=0.019), Luteinising hormone (p=0.002) levels, with values remarkably lower in high-PA group. Concerning psychopathological scales, the high-PA group showed worst Children's Global Assessment Scale (CGAS) scores (p=0.035). Regression analyses revealed that higher PA predicts higher delta BMI (p=0.021), presence of amenorrhea (p=0.003), lower heart rate (p=0.012), lower thyroid (Free triiodothyronine p<0.001, Free thyroxine p=0.029) and gynaecological hormones' levels (Follicle-stimulating hormone p=0.023, Luteinising hormone p=0.003, 17-Beta estradiol p=0.041). Concerning psychiatric measures, HPA predicts worst scores at CGAS (p=0.019), and at scales for evaluation of alexithymia (p=0.028) and depression (p=0.004).CONCLUSIONS: Results suggest that high levels of physical activity in acute AN associate with worst clinical conditions at admission, especially in terms of endocrinological and medical features.LEVEL OF EVIDENCE: Level III.