Can Exercise Cut Your Risk of Dementia?

Medically Reviewed

Strong bodies and strong minds go together. A recent study suggests that regular exercise can strengthen the brain and may cut your risk of cognitive decline and dementia down the road.

To determine how physical fitness affects brain health, researchers from Stanford University School of Medicine studied the medical records of 6,104 older patients in the U.S. Department of Veterans Affairs health system.

They found that the more vigorously the patients exercised, the lower their risk of cognitive problems (includng Alzheimer's disease years later. The findings were published in February 2017 in Mayo Clinic Proceedings.

The patients, average age 60 and nearly all men, were asked to run on a treadmill for as long as they could. The researchers then estimated the patients’ “metabolic equivalents,” which indicated how much energy they used while running based on peak treadmill speed and grade.

An average of about 10 years later, researchers examined patient records. Those who scored less than 6 metabolic equivalents on their treadmill test had a more than fourfold greater risk of cognitive impairment than those with scores higher than 12.

The risk of cognitive impairment dropped 8 percent with every 1-point increase in exercise capacity. Age, smoking, and high cholesterol were also identified as risk factors for cognitive decline.

How exercise helps the brain

As the U.S. population grows older, age-related cognitive disorders will become more prevalent—and with no medication to slow or stop the damage, learning how to prevent them will become more urgent.

Exercise stimulates the growth of cells in regions of the brain involved with memory as well as other areas. In part this is because of improved blood flow and oxygen as well as other brain-stimulating chemicals.

"The inverse association between fitness and cognitive impairment provides an additional impetus for health care providers to promote physical activity," wrote lead author Jan Müller, Ph.D., in the Mayo Clinic study.

The bottom line

If you’re not exercising regularly, start now. Speak with your doctor to plan a physical activity schedule that is best suited for your health needs and interests.

The research supports the benefits of exercise for the brain more than many previous studies, the authors say, because scientists followed people closely over time and relied on a diagnosis of dementia, Alzheimer’s, or cognitive impairment from a clinician.

“Of course, exercise alone—no matter how much or how intense—does not automatically confer immunity from life-threatening events such as heart attack or stroke, or even from Alzheimer’s,” says Peter Rabins, M.D., founding director of the division of geriatric psychiatry and neuropsychiatry at the Johns Hopkins University School of Medicine. “But even as little as 30 minutes of moderate levels of exercise a day can make a difference in overall brain health.”