UNIVERSITY PARK, Pa. — Helping residents become more physically fit may not just be a walk in a park, it could also be a walk to a park, according to a team of Penn State researchers.

In a study, the researchers found that small improvements to a city's ParkScore — an evaluation of a city's park system — could lead to more physical exercise for its residents. The Trust for Public Land created the ParkScore as an index to rank the park systems of the nation's largest 100 cities, they added.

"What we found was that the higher the ParkScore — which is a way of saying the better the park system — the larger the proportion of the population that was engaged in physical activity, and just a small positive change in that score can mean quite a bit as far as helping residents taking part in physical activity," said Lauren Mullenbach, a doctoral candidate in recreation, park and tourism management.

For example, the researchers said that a 10 point increase in improvement to the ParkScore of Atlanta, a city with 420,003 residents in 2014, would mean an additional 2,688 people would engage in leisure-related physical activity.

Cities with parks that are more accessible, spacious and adequately funded rank higher on the list, according to Mullenbach. The top five cities on the list include Minneapolis and St. Paul, Minnesota; Washington, D.C.; Arlington, Virginia, and San Francisco. Pennsylvania cities are in the top third of the list — Pittsburgh is ranked at 23 and Philadelphia is placed at 30.

According to the researchers, who present their findings in the current issue of Preventing Chronic Disease, city planners do not need to undertake dramatic programs to improve their parks to increase their residents' physical activity.

"Cities could do any number of things to increase their score, and some of the improvements are relatively straightforward," said Mullenbach. "They could spend more money on parks or park programming, expand their park acreage, or they could increase walking access by putting in sidewalks to the parks, or adding a few more entrances."

The researchers combined three nationwide public data sets to study possible relationships between parks, health and physical activity levels in 59 American cities. They used data from the Center for Disease Control and Prevention's 500 Cities Project, the Trust for Public Land's City Park Facts Report and the U.S. Census Bureau.

"We've known for years that there are aspects of city park systems that link to health outcomes, but we really never had the data — the evidence — to put this all together well," said Andrew Mowen, professor of recreation, park and tourism management, who worked with Mullenbach. "Lauren was able to tie this all together with those data sets."

Part of the problem with trying to research the health effects of city parks prior to the availability of these data sets was that earlier data might include data from suburban and county parks, according to the researchers.

"Normally, there's an effort from the Center for Disease Control to collect health information about people on a yearly basis from different municipalities — a mix of both metro counties and non-metro counties — across the country and they aggregate that health data to the metropolitan statistical area, so that could include the city and surrounding suburbs," said Mullenbach. "But, for this particular project, the CDC received funding to aggregate data just to the city boundary level, which has never been done before."

While the researchers found that a good park system was positively related to the residents' physical health, the effect was not statistically significant when accounting for demographics and other lifestyle factors.

"This could be because so many other factors — smoking, access to health care, are some examples — are crucial to health, too, that parks, or access to parks, really can't affect," said Mowen.

In the future, the researchers would like to examine how investments in park from public and private sources may affect physical fitness and health. They may also examine each contribution — access, funding and investment — separately to determine how they individually affect park quality and physical fitness and health.

"Another big message in this is that this is a collective effect," said Mowen. "It's not just the spending that planners have to work on, it's the collective of those three factors that have that impact."

Birgitta L. Baker, associate professor of professor of recreation, park and tourism management, also worked on the study.