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MIAMI (CBSMiami) — There’s new evidence that suggests keeping your body physically fit can also keep you mentally fit.

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The new study published in the Journal Neurology shows women who were very fit at age 50 were 88 percent less likely to develop dementia later in life.

Dr. Tara Narula is a cardiologist at Lenox Hill Hospital in New York.

While the study is small and involved only Swedish women, it tracked women for 44 years.

“It really adds to the growing body of evidence suggesting that fitness, particularly in midlife, may translate into your risk of dementia down the road,” said Dr. Narula. “By fitness, we’re talking about things you cannot control like age, gender, body size and genetics but also how physically active you are.”

In the study, they looked at about 190 Swedish women who were middle-aged and they gave them an exercise test. They grouped them by low, medium or high fitness levels and then followed them for about 40 years to see who developed dementia.

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Those in the highest fitness group, only about 5% developed dementia. About 32% developed dementia in the lower fitness group.

Dr. Narula said fitness seemed to delay the onset of dementia as well.

But how does it work? Dr. Narula explains.

“One of the theories is that you’re controlling your cardiovascular risk factors better by having better fitness. So you are decreasing blood pressure. You’re improving cholesterol, blood sugar, obesity risk,” said Dr. Narula. “You may be also changing the circuitry, the wiring, the connectivity of the brain, the actual brain structure.”

As for what you can do to attempt to prevent dementia, Dr. Narula says researchers say moderate levels of exercise will do the trick.

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“We’re not talking about running a marathon,” said Dr. Narula. “We spoke to the researchers. They said basically we’re talking about a moderate level of aerobic exercise.