Where You Live Can Impact Your Dementia Risk — Here’s Why

man walking over a lake

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Spending time outside can decrease your risk of developing certain degenerative diseases.

If you’ve ever complained about an ache or ailment to a doctor or loved one (or maybe a stranger), you’ve probably at least once been met with a seemingly random suggestion about going outside: “Try taking a walk” or “maybe you just need some fresh air.” (Thanks, doc — we don’t mind paying you hundreds of dollars for that very scientific advice.)

It seems like everyone believes a dose of the great outdoors can cure everything from nausea to brain fog to a stiff back. The truth is, sometimes it can. And recent research shows it can help older people avoid some really serious degenerative diseases. The healing power of nature is something most of us can grasp intuitively, but a new study suggests that the effects of being outside may have an even greater impact on our health than we previously thought. 

We’re breaking down the findings from a large-scale study that discovered even a limited amount of time spent in nature can lower the risk for dementia and other neurodegenerative diseases.

What did the study find?

Harvard researchers examined data collected from 62 million Medicare beneficiaries. They found that those who lived in zip codes with more greenery were hospitalized less for Alzheimer’s disease and related dementias, and Parkinson’s disease than their peers who lived in more densely populated urban areas. 

The researchers measured “green space” using an index that calculated the amount of land dominated by forest, grass, or copses of trees in a given region using satellite imagery. They also looked at “blue space,” areas close to bodies of water. (Parks and being near a lake, stream, river, or ocean were associated with a lower rate of hospitalization for Parkinson’s, but not for Alzheimer’s and dementia.)

Why is nature good for our cognitive health?

Smaller studies have also found that something about being in the great wide open is good for our brains. One published last year found that older Americans living in regions with lots of greenery had lower rates of dementia. Another conducted in the U.K., found that cognitive decline slowed over a 10-year period for people living in lush spaces.

Scientists aren’t quite sure why, but they’ve developed some compelling theories. Studies have found that being in nature can reduce stress. Plus, if you’re close to a hiking trail or park, you’re probably more likely to explore those spaces and get active. Both stress and a lack of exercise have been linked to higher rates of dementia. 

“Based on the available evidence, we can say that the more contact with nature, the better,” Payam Dadvand, a professor at the Barcelona Institute for Global Health who was involved in the U.K. analysis, told the Washington Post.

What are some other benefits of spending more time outside?

Immersing yourself in the natural splendor around us has been associated with a whole host of benefits, from alleviating anxiety and depression to lowering cancer risk to reducing blood pressure. One study done in Finland found that spending time in nature cut the odds of using blood pressure medication down by 36 percent. 

The Japanese are such strong believers in nature’s health benefits that they have a word for the process of going outside to heal: shinrin-yoku, which translates to “forest bathing.” The practice was developed in the 1980s and has proven so powerful it was incorporated into Japan’s health program. Along with a decline in stress and anxiety, researchers studying forest bathing also believe it may boost the immune system. Plants release a substance called phytoncides, which helps ward off insects. They found that when people are out for a stroll in the woods they inhale this chemical, which can raise their production of a type of white blood cell (natural killer cells) that fights tumors and viruses. It’s also gained some high-profile fans, including Kate Middleton. But it’s not like Americans weren’t wise to man’s need for lush environs too. As Walt Whitman once wrote: “Now I see the secret of making the best person: it is to grow in the open air and to eat and sleep with the earth.”

Suddenly, becoming one with nature doesn’t sound so corny.