Mother Nature Helps Kids with ADHD Concentrate 10-17-08

For children with attention deficit hyperactivity disorder, a 20-minute walk in the park may improve the ability to concentrate, a small study showed.

Children with ADHD performed significantly better on an objective test of concentration after walking through a park than when they walked through a residential neighborhood (P=0.0072) or a downtown area (P=0.0229), Andrea Faber Taylor, Ph.D., and Frances Kuo, Ph.D., of the University of Illinois Urbana-Champaign, reported in the October issue of the Journal of Attention Disorders.

The effect sizes were comparable to those obtained from treatment with methylphenidate (Ritalin) in other studies, they said.

"We can't say for sure that [taking a walk outside] would work for any given child," Dr. Faber Taylor said, "but there's probably very little risk involved in encouraging your child to play outdoors and seeing if their symptoms improve."

Previous studies have reported an improvement in concentration both in the general population and in children with ADHD after they spent time in a natural setting. The phenomenon might help explain why children with ADHD display fluctuations in performance on attention tasks, according to the researchers.

To explore the issue, they recruited 17 children (15 boys, two girls) ages seven to 12 (mean 9.23) who had been diagnosed with ADD or ADHD.

Half were taking daily medication year-round, 19% used medication on a variable schedule, and 31% were not receiving any drug treatment. None of the children took medication on the days of the study.

Following a period designed to induce attentional fatigue on three different days a week apart, each child took a 20-minute walk accompanied by an adult. One day they walked in a residential neighborhood, another day in a downtown area, and another one in an urban park.

After each walk, concentration was measured using the Digit Span Backwards test in which the child was required to listen to a series of numbers two to eight digits long and repeat them in the reverse order.

The walk through the park was associated with significant improvements in concentration compared with the walk through the residential neighborhood (effect size 0.71, P=0.0229) and through the downtown area (effect size 0.59, P=0.0072).

The researchers reviewed the literature and found that the benefits were of similar magnitude to those obtained by children with ADHD taking methylphenidate compared with healthy peers -- an improvement of about six-tenths of a point on the Digit Span Backwards test (effect size range -0.35 to 1.1).

"Thus," they said, "the effect of the park walk observed here is roughly equal and opposite to the performance deficit due to ADHD."

The children's subjective experiences were also more favorable during the walk in the park than with the other two; they rated the park as more fun (P=0.02).

The researchers said that the results were consistent with Attention Restoration Theory, which predicts that, for attention deficits related to attentional fatigue, exposure to a natural environment would have beneficial effects on concentration.

As part of that theory, environments deemed more favorable would yield greater benefits than those that require more "effortful, deliberately directed modes of attention," they said.

"Thus," they continued, "the marked fluctuations in performance typical of ADHD may reflect differential exposure to attentionally fatiguing and restorative environments, and more generally, attention fatigue and recovery brought on by different tasks and activities."

Although Drs. Faber Taylor and Kuo said that spending time outdoors may represent an inexpensive tool to aid in the treatment of ADHD -- one that can be implemented by schools and families alike -- they acknowledged some unanswered questions, including the durability of the effect.

"We have no objective performance data showing the effects of 'nature doses' lasting long enough to be of practical use in managing ADHD symptoms," they said.

In addition, they said, further research is needed to determine whether outdoor exposure benefits impulse control or academic performance.

Nevertheless, they said, sending kids outdoors does not have any adverse effects and is not associated with the social stigma attached to other treatments.

It may also have other positive side effects, including increased physical activity and lower rates of obesity, the researchers concluded.

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