Forget Tylenol. Your pediatrician might prescribe a walk in the woods.

(Melissa Cannarozzi/The Washington Post)

From a health perspective, Zarr said there are valid reasons for prescribing nature. His top three: To combat asthma, which is often exacerbated by indoor pollutants; to lessen some of the symptoms of Attention-Deficit Hyperactivity Disorder, which has been shown to respond well to outdoor play and, of course, to combat the modern scourge I wrote about last week, childhood obesity.

If you don’t want to wait for a prescription, join Zarr and parks advocates this Saturday in one of their other joint projects: The First annual National Kids to Parks Day . It’s a nationwide effort spearheaded by The National Park Trust to explore national, state or local parks.

The kickoff on the National Mall tomorrow might be soggy. The weather is expected to clear by Saturday, when families in the region are invited to Mason Neck State Park in Fairfax from 9 a.m. to noon for ranger walks, canoe demonstartions and other activities.

For those of us who can’t make it to Mason Neck, Zarr and his colleagues want us to get our families outside, somewhere green as soon as possible. Doctor’s orders.