Physical Activity and Post-treatment Weight Trajectory in Anorexia Nervosa

Objective: This study compared an objective measurement of physical activity (PA) in individuals with anorexia nervosa (AN) at low-weight, weight-restored, and post-treatment time points, and also compared PA in AN with that of healthy controls (HC).

Method: Sixty-one female inpatients with AN wore a novel accelerometer (the IDEEA) which measured PA at three time points: a) low-weight, b) weight-restored, and c) one month post-hospital discharge. Twenty-four HCs wore the IDEEA at one time point.

Results: Inpatients with AN became more physically active than they were at low-weight at weight restoration and following treatment discharge. Post-treatment patients with AN were more physically active than HCs during the day and less active at night, which was primarily accounted for by amount of time spent on feet, including standing and walking. Greater time spent on feet during the weight-restoration time point of inpatient treatment was associated with more rapid decrease in BMI over the 12 months following treatment discharge. Fidgeting did not differ between patients and controls, did not change with weight restoration, and did not predict post-treatment weight change.

Discussion: Use of a novel accelerometer demonstrated greater PA in AN than in HC. PA following weight restoration in AN, particularly time spent in standing postures, may contribute to weight loss in the year following hospitalization. © 2015 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:482-489).