Exercise and Treatment Outcome for Patients with Anorexia Nervosa

For most of us, gradually increasing daily exercise is a very good thing; however, for patients with anorexia nervosa (AN), increased physical exercise can sabotage treatment and lead to dropout. In addition, since patients with AN often deny exercising excessively, subjective measurement may underestimate the amount of actual physical exercise that patients undertake, according to researchers at Villa Garda Hospital, Verona, Italy.

Marwan El Ghoch, MD and co-workers designed a study to measure the effect of increased physical activity on the outcome of treatment of 53 patients with AN. They also compared the patients’ exercise levels to those of 53 age-matched controls (Int J Eat Disord 2013 May 25,  doi: 10.1002/eat.2214). To do so, they used a special armband (Sense Wear Armband; Body Media Inc, Pittsburgh) before and after patients received cognitive behavioral therapy in an inpatient setting. The subjects were all females with a DSM-IV diagnosis of AN who were consecutively admitted to the inpatient eating disorders treatment unit at Villa Garda Hospital. All participants were assessed with the Italian version of the Eating Disorder Examination (EDE).

The Sense Wear armband uses a two-axis accelerometer, a heat-flux sensor, a galvanic skin response sensor, a skin temperature sensor, and a near-body ambient temperature sensor to measure physical activity. The researchers combined this information with data on body weight, height, handedness, and smoking status to automatically calculate energy expenditure. The armband was positioned over the triceps of the dominant arm and kept in place for 4 consecutive days and removed only for bathing or swimming.

From the start, AN patients had higher exercise levels

Forty-three women with AN completed the 20-week treatment program, and 10 dropped out. The drop-outs had significantly higher baseline levels of moderate and vigorous exercise than did those who completed the study. (No other significant differences were identified between those who dropped out or other characteristics of eating disorders). The authors noted that the study showed that at baseline patients with AN had a higher activity levels than did healthy controls despite the fact that the patients were severely underweight, emaciated, and confined to the inpatient unit for the first week of treatment. Next, the women who dropped out of treatment had exercise intensity levels nearly twice those of women who completed the study. Third, among women who completed the treatment showed substantial improvement in body weight, eating disorder symptoms, and general psychopathology.

However, despite all the improvement, completers showed a significant increase in the number of daily steps, as well as duration of time spent exercising and energy expenditure during exercise—nearly twice that of healthy controls. The authors noted that they were unable to conduct a longitudinal assessment of physical activity after the women were discharged and thus could not determine if the increase in physical activity might play any role in relapse. The findings suggest that making a precise assessment of physical activity may help identify patients who have a potentially higher risk of dropping out of inpatient therapy.