Washington, D.C., pediatricians are prescribing a simpler medicine for some of their patients: parks.

In fact, many doctors have started to recognize the positive impact nature has on many health conditions, says Dr. Robert Zarr, founder and director of DC Park RX, a new community health initiative. “Nature clearly shows an effect on your health in terms of prevention,” he says. “So you may not have a diagnosis yet, but if you’re headed that way, you can certainly turn that around by spending more time outside.”

DC Park RX has a searchable online database of parks—350 green spaces. The searchable database enables the doctor of an obese child who likes to play basketball, for instance, to find a nearby park with basketball courts for him to go to. Doctors can even print out the information with directions and provide it to the patient along with other medical chart information.

Children who have been prescribed time in parks are getting an additional 22 minutes per week of physical activity and are spending six more days per year at a park for at least 30 minutes, according to Zarr’s preliminary results. Zarr soon hopes to provide actual health changes as a result of park prescriptions, such as body mass index and blood pressure decreases.

Many studies have touted the idea that physical activity in nature offers health benefits, even though DC Park RX is one of the first programs to give doctors a tool to actually prescribe parks. Parks are continually being recognized as critical to medically treating chronic disease and mental illness. In fact, Dr. Daphne Miller, a professor of family and community medicine at the University of California in San Francisco, said green spaces are crucial to solving hypertension, anxiety, depression and diabetes—what she calls “the diseases of indoor living.”

Zarr plans to expand the program across the city.

Also read:

Inspiring Outdoor Play

Greener Spaces, Smarter Kids