Get a Daily Dose of Green Space to Lower Dementia Risk

By | July 12th, 2018

A new study suggests that people who living in neighborhoods rich with greenery experience a slower cognitive decline than their urban-dwelling counterparts.

When you close your eyes and go to your “happy place,” does it involve the great outdoors? If so, there may be a good reason for that, according to a new study. Scientists at Barcelona Institute for Global Health found that living in a neighborhood with more green spaces is beneficial to your health and may even slow cognitive decline in older people.

Scientists have found that more time in green space provides stress relief and can even soothe mental illness.

In the past, studies have shown that a lack of green space translates to poorer health and higher crime and violence rates. According to experts, this dates back to the days before technology brought us out of caves and into sprawling cities. In less green spaces, our brains perceive a threat: The air quality is poor, heat rises and anxiety from the lack of greenery triggers a cortisol response in the brain. Now, researchers have found that these factors might add up to a speedier cognitive decline.

For this study, scientists followed 6,500 people in the U.K. between the ages of 45 and 68 for 10 years. Researchers checked in with participants at three different times during the study and had them complete extensive cognitive testing that involved verbal and mathematical reasoning and short-term memory. After analyzing the results at the end of 10 years, they compared the rate of cognitive decline to satellite pictures of green space in participants’ neighborhoods. They found that those who lived in areas with abundant greenery had a slower cognitive decline than their more urban-dwelling counterparts.

A lack of green space can also determine other factors that researchers said might contribute to the rate of decline.

“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),” said Carmen de Keijzer, first author of the study. “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.”

In fact, just a short walk through green space can influence your mood. In a 2017 study, adults who walked through green spaces showed a rapid shift in neural responses when they moved from greenery to concrete.

Does that mean that green spaces like forests and parks are the key to a healthy brain? Maybe, but study authors emphasize that the difference in cognitive decline was small—4.6 percent. And the correlation between green spaces and slower cognitive decline was stronger in women, which researchers need to unpack more, as only 30 percent of the participants were female. But even a small percentage should not be brushed off as inconsequential.

“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,” said Payam Dadvand, an ISGlobal researcher who worked on the study. “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.”

As the population ages, urban planning may take a cue from studies like this in order to provide more green space in developing areas.

This study was published in the journal Environmental Health Perspectives.

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