Roughly 5.8 million Americans have Alzheimer’s disease and related dementias, according to the Atlanta-based Centers for Disease Control and Prevention. Changing your lifestyle to include exercise, however, might reduce your risk, a new study suggests.

Researchers at the George Washington School of Medicine and Health Sciences found a link between physical fitness and the risk of developing symptoms of dementia. The study observed 649,605 military veterans between the ages of 30 and 95 over an eight year period. The researchers split the participants into five groups based on metabolic equivalence of task — or METs.

Metabolic equivalence of task measures the rate of energy expended per unit of time relative to your resting metabolic rate. That means if your MET is at four, you would be expending four times the amount of energy than you would be when resting, according to Healthline.

To put MET measurement into perspective, activities like watching TV or sitting would measure 1 MET, leisurely biking measures to 4 MET, and rope jumping measures to 10 MET.

When comparing the five groups, the researchers discovered the fittest group, which achieved the highest METs, were 33% less likely to develop Alzheimer’s disease and related disorders. The second fittest group was 26% less likely, the third 20% less likely and the fourth 13% less likely, according to the study.

“You cannot prove that it was the low fitness that caused dementia,” Dr. Scott Kaiser told Medical News Today.

“But, that said, the association was so clear, not just in the strength of the association but in the nature of the association,” he added. “The way it so neatly correlated with rising fitness levels lowering dementia risk. It’s a very convincing association.”

The full study will be presented in April at the American Academy of Neurology’s 74th annual meeting in Seattle.

According to the Mayo Clinic, there are 12 risk factors of dementia that can be modified, and 40% of dementia cases fall under these risk factors. These risk factors are poor diet and exercise, excessive use of alcohol, cardiovascular risk factors such as high blood pressure, depression, diabetes, smoking, air pollution, sleep disturbances, head trauma, vitamin deficiencies and medications that can worsen memory.

Age, genetics and sex are three factors that cannot change your risk of developing dementia. However, Kaiser said, “If they have more genetic risk, my patients need to focus on their cardiorespiratory fitness as part of their overall brain-healthy lifestyle.”

Exercises that can improve cardiorespiratory fitness include running, walking, swimming, jump rope and high-intensity sports, according to Medical News Today. Additionally, exercise has other benefits and reduces risks of some cancers, high blood pressure, poor mental health and Type II diabetes, according to Medline Plus.

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