Stimulant medications decrease energy expenditure and physical activity inchildren with attention-deficit/hyperactivity disorder

Objective: To determine the effect of stimulant medications used to treat c hildren with attention-deficit/hyperactivity disorder (AD/HD) on energy exp enditure, fuel utilization, and physical activity. Study design: Energy expenditure and physical activity were measured, respe ctively, by room respiration calorimetry and microwave motion detectors in 31 children with AD/HD (26 boys and 5 girls; ages 6 to 12 years) both while they were receiving their prescribed stimulant medication and after the me dication had been discontinued for at least 24 hours. Fuel utilization was calculated from calorimetry data. Results: Total and awake energy expenditure including energy expended while doing schoolwork, riding a stationary bicycle, resting, and watching a mov ie were from 4% to 8% lower when the children were receiving their prescrib ed stimulant medication. Total and awake activity were also lower while the y were receiving medication (16% to 22%) and accounted for the lower rates of energy expenditure. Sleeping metabolic rate, basal metabolic rate, and f uel utilization were unaffected by medication. Conclusions: Stimulant medications decrease physical activity and hence, de crease the activity component of total daily energy expenditure in children with AD/HD.