Photo by Jeremy Blanchard.

“Parks are a part of our healthcare system,” said Daphne Miller, a professor of family and community medicine at the University of California, San Francisco. These green spaces are crucial to solving hypertension, anxiety, depression, diabetes — “the diseases of indoor living.”

But parks officials and the medical profession still need more data to take aim at the many “naysayers on the other side” who don’t believe in what landscape architects (and many urban residents) value, Miller said. Luckily for all of us, a few scientists are doing innovative research, trying to capture that data.

Miller was speaking at a recent conference in New York City called Greater & Greener: Reimagining Parks for 21st Century Cities. In a separate panel on health care and parks, Deborah Cohen, senior natural scientist at RAND, and Sarah Messiah, a research professor at the University of Miami, presented some exciting results.

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In a National Institutes of Health-financed study, Cohen has used “systematic observations” measuring “play in communities” to determine if and how people burn calories in parks (see downloadable app). Her team of researchers visited parks and counted people in target areas every hour, three or four days a week. Cohen was particularly interested in “vigorous” physical activity such as brisk walking, jogging, or running — the healthy kind of activity needed to get hearts pumping.

She said some 50 percent of all vigorous activity occurs in parks. Unfortunately, that doesn’t say much, because “hardly anyone engages in vigorous activity anymore.” For boys, the average is two minutes a day, and for girls, just one minute a day.

To measure the impact of new parks on activity levels, Cohen did a before and after study. She watched residents in low-income, high-crime areas in Los Angeles before and then after three pocket parks were installed. These are tiny parks (less than half an acre), mainly playgrounds, which aren’t staffed. She found that for two of them, “the parks were better used than the larger parks serving larger areas.” People were “more likely to walk to the smaller neighborhood parks, which were perceived to be safer than the larger neighborhood park.” Walking gets the heart pumping.

Then, Cohen evaluated 12 “fitness zones”  — places in L.A. parks where the Trust for Public Land has installed outdoor exercise equipment. Of the 23,500 people who used the parks during her study, some 2,500 were in the fitness zones — two to four people each hour on average. She said these fitness zones led to “increases in moderate, vigorous activity” and were “relatively cost-effective”: At $45,000 a piece, with a 15-year lifespan, these systems offer 11 cents per metabolic equivalent of task (MET), referring to the metric for measuring the energy use of physical activities. “Anything under 50 cents per MET is worth it,” she said.

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Benefits did not necessarily increase with the amount invested. When Cohen looked at the MET value of new facilities costing upwards of $1 million, she found that in one park, after the major improvements, the use actually fell from 2,000 to 1,500 people a day. The culprits? Reduced hours, cut programs, less maintenance, and a shorter baseball season. “Less was happening so people went less,” she said. Apparently facilities aren’t everything.

In fact, in another experiment, some parks were given $4,000 to spend on signage, courses, activities, and other programming, while a “control group” didn’t receive any money. The “control” parks saw user levels fall, while the intervention parks saw increased users.

Sarah Messiah with the Miller School of Medicine at the University of Miami and the Miami-Dade County parks and pediatrics department is focusing her research on parks and childhood obesity. Thirty percent of American children are now obese, she said. She’s now seeing lots of kids with scary adult diseases like fatty liver disease and metabolic syndrome. “This generation could be the first that has a shorter lifespan than their parents.”

Miami-Dade County has the third largest park system in the U.S., with more than 260 parks over nearly 13,000 acres, visited by 10 million people annually. With the park system as a platform, Messiah and local parks officials used Fit2Play, a national wellness program, and SPARK after-school programs. For a year, kids from “dangerous” low-income neighborhoods were bused in after school. They spent an hour doing homework and then an hour of SPARK programs in the park.

The researchers found that the after-school programs were extremely beneficial. “The kids were growing normally” instead of ballooning up abnormally, Messiah said. “There were statistically significant decreases in blood pressure,” which is “just important as weight.” Test performance “significantly improved over the year.” The kids’ knowledge of nutrition improved, too.

Messiah said the key to the program’s success was the partnership between the parks system and the university. “This was a team approach with lots of fluid communication both ways.” She said it was also important to get parents to buy in and “sign those participation forms.”

Messiah and Cohen’s programs show that parks not only provide a safe place for people (and especially kids) in dangerous neighborhoods, but are possibly key to their health and well-being. However, park space alone isn’t enough. The park programs are equally as critical.

Without these opportunities, Messiah said, kids in these dangerous neighborhoods just sit inside, playing video games, eating junk food, growing into sedentary unhealthy adults disconnected from nature.

Cohen put it this way: “There’s lots of competition for leisure time. Parks need to compete.”