While inmates at maximum security prisons in the U.S. are guaranteed at least 2 hours of outdoor time a day, half of children worldwide spend less than an hour outside, reports TreeHugger.com.

A survey of 12,000 parents in 10 countries found that one-third of children (ages 5 to 12) spend less than 30 minutes outside each day. The survey, sponsored by Unilever laundry detergent brands OMO and Persil, inspired a new marketing campaign – “Dirt is Good – Free the Children.”

The short film below – documenting prisoners’ responses to the survey – is part of that campaign.

Prisoners at a maximum security facility in Indiana called outdoor time the “highlight” of their day. “You take all your problems and frustrations and just leave them out there,” one prisoner said. Another said “it keeps his mind right.”

When asked how they would feel about having their “yard time” reduced to one hour a day, inmates responded that it would build more anger and resentment. One inmate said it would be “torture.” A prison guard said it would be “potentially disastrous.”

The prisoners are shocked upon learning that most children have less than an hour of outdoor time per day, one of them calling the news “depressing.” Another said if he could have one wish granted it would be that he could take his kid to a park.

Another study found that one in nine children “have not set foot in a park, forest, beach or any other natural environment for at least 12 months.”

Huffington Post reported recently that with children today spending only half the time their parents did outdoors, we are producing an “unsociable, unimaginative and inactive generation.” Only half of children have ever built a sandcastle at the beach or had a picnic outside of their own yard, and over a third have never played in the mud. Also, about half of children opt for screen time alone over playing with others outdoors.

In addition to “unsociable, unimaginative and inactive” – our culture’s lack of outdoor time is producing children who are physically and mentally ill:

We are physically active when we spend time outdoors, so we are less likely to become obese. When sunshine hits our skin, we form Vitamin D, which helps with a number of health issues. Peer-reviewed scientific studies have shown that time spent outside lowers rates of heart disease, osteoporosis, multiple sclerosis, and some forms of cancer. Kids with ADHD focus better when they spend time outdoors. And, nature time leads to more positive moods, as well as lower stress and anxiety.

Reprinted from Return to Now