There are lots of choices about where to live when you retire. Some people like the idea of college towns where there's never a lack of culture, while others prefer big cities where there's plenty to do. But a recent analysis has found that living in rural areas filled with green space is the key to keeping your mind sharp.

Researchers think a more active lifestyle, as well as less pollution, noise and stress may all play a part in cognitive function.

For the study, researchers looked at 10 years' worth of data, following more than 6,500 people living in the United Kingdom between the ages of 45 and 68 years old. The participants took a series of cognitive tests at three different points during the study period. The tests assessed their verbal and mathematical reasoning, verbal fluency and short-term memory and tracked how their functioning declined in these areas each time.

The amount of neighborhood green space was estimated using satellite images.

Researchers found that mental decline was 4.6 percent less over the 10-year period for people living in the countryside with lots of green space versus urban areas

"There is evidence that the risk for dementia and cognitive decline can be affected by exposure to urban-related environmental hazards (such as air pollution and noise) and lifestyle (such as stress and sedentary behavior)," says lead researcher Carmen de Keijzer from the Barcelona Institute for Global Health, in a statement.

"In contrast, living near green spaces has been proposed to increase physical activity and social support, reduce stress, and mitigate exposure to air pollution and noise."

The power of green space

senior couple walking dog in the countryside A more active lifestyle and less pollution may be why living a rural life is better for cognitive functioning than being in the city. (Photo: Monkey Business Images/Shutterstock)

In the study, which was published in Environmental Health Perspectives, researchers point out that recent evidence has shown cognitive benefits of green space exposure in children, but earlier studies on the possible relationship with older adults has been scarce, and with inconsistent results.

The results of the study found that the association between rural living and slower cognitive decline was stronger among women than in men.

According to researchers, the proportion of people over 60 years old in the world is expected to nearly double between 2015 and 2050 with the number of dementia cases predicted to grow at a similar rate globally.

"Although the differences in cognitive decline observed in our study are modest at individual level, they become much more significant if we consider these findings at population level," says study co-author Payam Dadvand. "If confirmed by future studies, our results may provide an evidence base for implementing targeted interventions aimed at decelerating cognitive decline in older adults residing in urban areas and hence improving their quality of life."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.