In the study 17 children with ADHD were given guided walks in a city park and two other urban settings, then given concentration tests. The study found significant improvements in concentration following the walk in the park compared with the urban walks. However, the reliability of these findings is limited.

The study had a very small sample size and the results come from only a single exposure to each environment. Whether results could be replicated, sustained in the long-term, or produced in everyday situations is unclear. Also the study did not directly compare the effectiveness of walks to ADHD medication, but instead used data from other studies. The question of whether ‘a walk in the park’ is as good as drugs for ADHD requires further research. Nevertheless, all children benefit from fresh air and exercise and this should be encouraged wherever possible.

Where did the story come from? Andrea Faber Taylor and Frances E. Kuo of the University of Illinois carried out this research. The study reported no sources of funding and was published in a medical journal, the peer-reviewed Journal of Attention Disorders.

What kind of scientific study was this?This was a within-subject randomised crossover trial where a group of children with ADHD were each exposed to a guided 20-minute walk to see how each of the walks affected subsequent concentration. These walks, given in a random order, were in either a city park, downtown area, or an urban neighbourhood.

This study was adding to investigations into why performance related to attention can vary so much in children with ADHD, and what may influence this. This study explored how elements of Attention Restoration Theory, (the idea that individuals experience a sense of rejuvenation after exposure to the natural environment) might apply to managing symptoms of ADHD.

Children aged 7-12 years with professionally diagnosed ADHD were recruited through local advertisements. The final sample included 17 children – 15 boys and two girls (reflecting the male predominance of ADHD) – who were on average 9.2 years of age. Each of the walks were carried out on separate occasions, in the daytime in warm summer weather, and the children were individually accompanied by a guide, whom they had some time to get to know before the session started.

Although half of the children were taking daily medication for ADHD, none took this on the day of the walk. A series of puzzles were completed before the start of the walk (in an indoor setting), which were designed to cause some degree of lapsed attention during completion. Following this, a 20-minute relaxed walk was taken with the guide, with minimal conversation during the walk.

Upon arrival back at the indoor setting, the child completed tests of concentration administered by a person who was unaware of where the walk had taken place. Tests included the Digit Span Backwards (DSB) test (repetition of a given sequence of numbers/digits in the reverse order) and other word and vigilance tests.

The children also related their experience of the walk, rating options such as fun, relaxed, boring etc. The children were all told that they could receive a toy from a treasure chest after completing the tests.

What were the results of the study?Children with ADHD had significantly improved concentration following the walk in the park compared with the walks in both the downtown and neighbourhood settings. The park walk resulted in improved performance in the Digit Span Backwards test: children were on average six-tenths of a digit better at the test than after the downtown walk and seven-tenths of a digit better than following the neighbourhood walk. There were no significant differences in concentration between the two urban walks. Children also rated the park walk as ‘fun’ significantly more often than the two urbanised walks.

Previous studies have shown that children with ADHD have Digit Span Backwards scores on average six-tenths of a digit lower than for those without ADHD. Therefore, the researchers say, the effect of the park walk is "roughly equal and opposite to the performance deficit due to ADHD".

Comparing effect sizes to other studies of methylphenidate (Ritalin – the drug commonly used to treat ADHD) that had used a cognitive performance measure (‘roughly comparable to DSB’), they suggest that the effect of the park walk was ‘roughly equal’ to that of the medication.

What interpretations did the researchers draw from these results? The researchers conclude that children with attention deficits have better concentration after walking in a park than two other urban settings.

They also say that the effect of ‘a dose of green’ was substantial, and roughly equal to that seen following extended-release methylphenidate such as Ritalin. They also conclude that a walk in the park was a positive experience for the child.

What does the NHS Knowledge Service make of this study?This study has demonstrated the benefits of a park walk compared to walking in two urban settings on a measure of concentration. However, there are important points to bear in mind:

The sample size was very small, including only 17 children with attention disorders. A much larger study sample would add strength to the findings and help to demonstrate more convincingly that these improvements in concentration are seen.Additionally, randomisation of larger groups of children to experience only one type of walk (instead of all three in a random order) would allow comparison between the groups would be beneficial.The study did not compare walks against treatment with Ritalin or other drugs for ADHD, and has only made indirect comparisons to other studies. This is not an adequate method for comparing treatments for a number of reasons, including different study methods, different measures of attention and different populations of children.The results are only from a single exposure to the park environment. Questions remain unanswered as to whether results could be replicated, sustained in the long-term (i.e. attention maintained for hours or days following the exposure), or how regular the walks would need to be tin order to maintain benefit, remain to be answered.Likewise, it is unclear whether the same effect would be seen if the child was out on their own/playing with friends rather than in the more artificial scenario of being under silent supervision of a guide whom they did not know particularly well.As the researchers acknowledge, their study is also unable to assess whether environmental exposure has any effect upon impulse control, which alongside attention deficit is another particular challenge of ADHD.It is unclear whether any improvements in concentration or impulse control resulting from environmental exposure would actually have an effect upon academic performance or peer group/family situations. The question of whether ‘a walk in the park’ is as good as drugs for ADHD requires further research. Nevertheless, all children benefit from fresh air and exercise and this should be encouraged wherever possible.

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