Children with attention deficit hyperactivity disorder (ADHD) could be at greater risk of becoming obese, a study in the Journal of the American Academy of Child & Adolescent Psychiatry shows. “We found that ADHD was a risk factor for later obesity,” said Alina Rodriguez, a visiting professor at Imperial College London, UK, whose recent study found that children with ADHD symptoms were less likely to engage in physical activity and more likely to become obese as adolescents.
This may sound counterintuitive to the image most people have of a child with ADHD: sprightly and in constant motion. How could someone who can’t sit still ever become lethargic and paunchy? Kids with ADHD, though, are more squirmy than energetic, and both inattention and impulsivity — defining characteristics of ADHD — could increase the risk of obesity.
“It may seem paradoxical,” said Samuele Cortese, M.D., Ph.D. and clinical associate professor at Southampton University, UK, “rather than being hyperactive, individuals with obesity are often described as ‘lazy.'”
ADHD is the most commonly diagnosed disorder among U.S. children ages 4-17. It affects nearly seven percent of children and adolescents as of 2011, according to the Centers for Disease Control and Prevention (CDC). Medications such as Ritalin (methylphenidate) and Adderall (dextroamphetamine) typically increase attention span and lessen impulsivity. What’s more, a common side effect of these stimulant medications is appetite suppression. Left untreated, however, ADHD could lead to indolence.
Obesity affects over a third of U.S. adults, according to the Journal of the American Medical Association (JAMA). The most commonly diagnosed psychiatric disorder could be the root of a problem plaguing more than half the adults in the U.S.
Rodriguez and her team followed over 6,500 children from age 8 to age 16 and found that nine percent who had ADHD symptoms as children were more likely to be physically inactive and obese as teens. Physical activity, or lack thereof, seems the underlying factor. “The main take-away [from the study] is that physical activity really had a moderating impact on obesity,” said Rodriguez. Since children with ADHD play less, they are significantly more susceptible to obesity as adolescents.
“It is self-evident that engaging in physical activity (at school and also outside of school) is important, and it might be even more important for children with ADHD since they might be at higher risk of obesity,” said Cortese. But why are children with ADHD less inclined to exercise?
“A lot of 8-year-olds like to sit in front of the computer,” said Rodriguez. One to two hours spent watching television or playing on the computer is acceptable, according to the American Academy of Pediatrics, but research has shown children spend over six hours per day sitting in front of screens. That number is even larger for those with ADHD, said Cortese. “Children with ADHD have been shown to exercise less and watch more TV than children without ADHD.”
Kids already spend six to seven hours on average sitting in school and they barely get any time to burn off energy on the playground. Mathew Pontifex, a professor of Kinesiology at Michigan State University, points to an underlying problem in school funding. “It’s increasingly being tied to achievement scores, and that means cutting opportunities for physical activity for additional time in the classroom,” said Pontifex. These cuts hurt children with ADHD the most.
To be sure, ADHD is merely one of many potential risk factors for later obesity. Both Rodriguez and Cortese hesitate to identify one sole cause for why children with and without ADHD become obese. “We are trying to uncover causal risk factors for ADHD. If we can change or eliminate a cause then we may be able to potentially prevent or ameliorate ADHD symptoms,” said Rodriguez.
One thing is for certain, though: regardless of whether children have ADHD, they need more exercise. “Physical activity is good for you anyway, and there are a lot of studies that show it helps mental health,” Rodriguez said. Help mental health and stave off obesity? Exercise sounds like the best medicine.
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Pontifex, M. B., Saliba, B. J., Raine, L. B., Picchietti, D. L., Hillman, C. H. (2013). Exercise improves behavioral, neurocognitive, and scholastic performance in children with attention-deficit/hyperactivity disorder. The Journal of Pediatrics. doi:10.1016/j.pjeds.2012.08.036.