In the summer of 2008, researchers from the University of Illinois, Urbana-Champaign, gathered a group of especially animated children—they all had been officially diagnosed with ADHD—and administered a simple treatment: a 20-minute walk in a park.
The Urbana-Champaign team, led by Frances Kuo, a psychologist who studies how trees, green space, and other natural features affect human health, had read reports from parents who said their children’s ADHD symptoms seemed to improve when they participated in after-school programs that took place outdoors. Kuo and her team wanted to find out if these reported improvements were consistent. They started by giving each child a standard concentration test that involved listening to a sequence of numbers and then repeating it back in reverse order. Then they took them for walks. Some children were taken to a downtown area, others to a residential neighborhood, and a third group to a park. Then they were given the concentration test again.
The results were remarkable. The children who had taken walks in the downtown or residential areas showed no improvement in concentration. But those children who had taken a walk in the park showed improvements that effectively canceled out their ADHD. A 20-minute walk in a natural environment was about as effective as common ADHD medications, the team concluded.