Heat reversal of activity-based anorexia: implications for the treatment of anorexia nervosa.
Activity-based anorexia (ABA) provides an animal model of anorexia nervosa (AN). In this model, rats given restricted access to food but unrestricted access to activity wheels, run excessively while reducing food intake, lose a sizeable percentage of body weight, become hypothermic, and can fail to recover unless removed from these conditions. Once rats had lost 20% of body weight under standard ABA conditions, they were assigned to one of two ambient temperature (AT) conditions. Increased AT reduced running rates and led to weight gain in active rats. The effect of increasing AT on food intake was dependent on whether the rats were sedentary or active. Although warming reduced food intake in the sedentary rats their body weight remained stable, whereas in active rats increased AT did not reduce food intake and weight gain gradually rose. From a translational perspective, these findings offer a fresh perspective to the disorder, and underscore the need for further studies to assess the effects of heat treatment in patients as an innovative adjunctive treatment for anorexia nervosa.