Exercise performance and body dimensions in anorexia nervosa before and after rehabilitation

The boys and five girls (mean age 15.0 y.) with anorexia nervosa (AN) were studied before and after a treatment which restored their body weight to normal. Before treatment the patients' average weight loss was 25% of their premorbid weight. The function and dimensions of the oxygen transport system were determined with heart (HV) and blood (BV) volumes, lean body mass (LBM) and exercise tests on a bicycle ergometer with determination of maximal aerobic power (VO2 max). Before treatment, the patients had bradycardia and hypotension. HV and BV decreased in proportion to the loss of body weight. During maximal exercise, attainable oxygen uptake and heart rate were low. VO2 max decreased out of proportion to the circulatory and body dimensions. After treatment, HV and BV increased in proportion to the rise in body weight. LBM increased significantly in all patients. Heart rates at rest and during exercise were within the range of normal and VO2 max increased. It is concluded that the circulatory system is highly adaptive to the low caloric intake in AN and is totally normalized after weight gain.