Hint: You'll want to have those sneakers handy.

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We know that aerobic activity is important for muscle strength, a healthy heart and to give your lungs a workout. Scientists are discovering another fascinating way something as simple as walking can improve your health: by increasing blood flow to your brain, which may, in turn, lower your risk for dementia.

When 70 men and women between age 55 to 80 with diagnosed mild memory loss followed a specific exercise program for one year, the blood flow to their brains increased, according to a March 2021 study in the Journal of Alzheimer's Disease.

And this news might hit home to more of us than you'd imagine: As many as one in five people 65 and older experience some form of mild cognitive impairment (MCI), which might affect memory, decision-making, or reasoning skills. In many cases, MCI progresses to dementia, including Alzheimer's disease.

Cut out of head with plants growing on a designed background
Credit: Getty Images / Paula Daniëlse

Participants in the study by researchers at UT Southwestern were randomly assigned to one of two groups for 12 months:

  • 3 to 5 weekly stretching sessions, each lasting 30 to 40 minutes
  • 3 to 5 weekly brisk walks, each lasting 30 to 40 minutes

Both groups were supervised by exercise physiologists for the first four to six weeks, then the participants logged their own workouts and wore a heart rate monitor as they exercised.

Among those who completed the study and fell in the aerobic group, they displayed less stiff blood vessels in their necks and had more blood flow to their brains. Those who stretched didn't experience similar changes.

"There is still a lot we don't know about the effects of exercise on cognitive decline later in life. MCI and dementia are likely to be influenced by a complex interplay of many factors, and we think that, at least for some people, exercise is one of those factors," says C. Munro Cullum, Ph.D., professor of psychiatry at UTSW and co-senior author of the study.

It's too soon to say from this study if the increased blood flow might directly impact memory or other cognitive function, but an increase in blood flow could precede changes to cognition, the researchers say. This finding will help direct their future research.

"This is part of a growing body of evidence linking exercise with brain health," says study leader Rong Zhang, Ph.D., professor of neurology at UTSW. "We've shown for the first time in a randomized trial in these older adults that exercise gets more blood flowing to your brain."

Earlier research proved that less blood flow to the brain is correlated to dementia, and other studies have hinted at the fact that regular aerobic exercise might boost cognition and memory later in life. More deep-dives are needed to make a direct link and to prove that exercise is the cause for these brain-boosting effects.

"Having physiological findings like this can also be useful for physicians when they talk to their patients about the benefits of exercise. We now know, based on a randomized, controlled trial, that exercise can increase blood flow to the brain, which is a good thing," Zhang says.

In addition to memory, check out several ways physical activity improves your mental health and mood. Need some help getting started with a regular routine? Try this 21-day walking workout jumpstart!