In your 40s and not exercising? New research says your brain may shrink

Not being physically active in your 30s and 40s may be linked to smaller brain size 20 years later, which could accelerate brain aging, according to new research.

“We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging,” said study author Nicole Spartano, with the Boston University School of Medicine in Boston.

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The participants were part of the Farmington Heart Study, which started in the 1940s as a way to track aging and its impact over decades.  For this study, 1,583 people took part with an average age of 40 and without dementia or heart disease.

WATCH: Nicole Spartano talks about her research that finds poor physical fitness in middle age may be linked to a smaller brain size 20 years later.

Researchers had participants perform a treadmill test to measure cardiovascular health.  Researchers noted the study was observational, it does not prove that poor physical fitness causes a loss of brain volume; it shows the association.

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The study also showed that “people whose blood pressure and heart rate went up at a higher rate during exercise also were more likely to have smaller brain volumes two decades later.”

“While not yet studied on a large scale, these results suggest that fitness in middle age may be particularly important for the many millions of people around the world who already have evidence of heart disease,” she said.

The results were published in the online issue of Neurology, the medical journal of the American Academy of Neurology.