Getting women to meet the U.S. federal government's recommended level of moderate-to-vigorous physical activity remains a huge challenge. A large new study shows that where women live affects just how likely they are to exercise.

The study, appearing online and in the November issue American Journal of Preventive Medicine, found that women throughout the United States, in both urban and suburban areas, were more likely to walk where they felt safe and had access to sidewalks and other community resources.

"The results from this study confirm what we know about the health benefits of living in neighborhoods with access to recreation facilities and resources such as shops and stores," said Keshia Pollack, assistant professor at the Johns Hopkins Bloomberg School of Public Health, who is familiar with the study.

"The bottom line is when people have access to these types of resources, they are more likely to meet physical activity recommendations," said Pollack, who specializes in formulating policies to create safe and healthy environments.

Researchers from Purdue University evaluated responses from almost 69,000 women between ages 40 and 60 who took part in the Nurses' Health Study II in 2005. The survey asked women whether they had shopping and free recreational facilities within walking distance, whether they had sidewalks and about their perception of crime in the area. Women also responded to items on how much time they spent walking, running or biking outdoors.

Just 24 percent of the women met the recommended activity level calculated by time spent and pace used for walking, jogging, running or bicycling, or combinations of those each week.

The study found that an increase in positive environmental characteristics improves the odds that women will be physically active in all regions of the country. Crime had a negative influence on physical activity in most regions. Having sidewalks made it more likely for women to meet weekly walking guidelines in the Midwest and South, but not in the Northeast and West.

"We need policies that create healthy and safe environments where people live, work, and play," Pollack said.

Troped PJ, et al. Perceived built environment and physical activity in U.S. by women by sprawl and region. Am J Prev Med 41(5), 2011.