Aerobic Exercise and Memory: How Are They Connected?

Aerobic exercise — the kind that makes you breathe harder and gets your heart rate up — can benefit your brain in several ways. There’s more to learn, but recent research suggests that aerobic activities like dancing, cycling and brisk walking may help improve your thinking and memory skills by boosting blood flow to the brain. That blood supply brings the oxygen and nutrients the brain needs to function at its best.

In a 12-month study of 56 cognitively healthy adults in their 60s and 70s published in the Journal of Cerebral Blood Flow & Metabolism in 2022, participants were randomly assigned to either aerobic exercise training — exercises that significantly raised their heart rate — or a stretching and toning program. All participants received MRIs and cognitive and cardiovascular tests at the beginning and end of the trial.

The aerobic exercise group began with three 25- to 30-minute workouts per week and gradually increased to four or five 30- to 40-minute workouts per week; two of them were high-intensity. The stretching and toning program had a similar time commitment for stretching and gentle strengthening exercises using light resistance bands.

Compared with the stretching and toning group, those in the aerobic exercise group had better blood flow to the brain and better performance in memory.

A similar study of 30 adults with mild cognitive impairment, published in the Journal of Alzheimer’s Disease in 2020, also showed benefits of aerobic activity. Half of the participants, in their late 50s to early 70s, did 12 months of aerobic exercise training while the rest did only stretching. Based on brain scans to map changes in blood flow, the researchers found that aerobic exercise improved blood flow to two key regions of the brain associated with memory.

At the one-year mark, the aerobic exercise group showed a larger improvement in some memory scores than the stretching group, researchers reported.

These studies suggest that increased blood flow from aerobic exercise is linked to reduced risk of memory loss, said Binu Thomas, assistant professor in neuroimaging at the University of Texas Southwestern Medical Center and coauthor of the 2020 report. “By adding as little as four weeks of exercise, you start seeing cardiorespiratory fitness improvement, which is definitely beneficial for brain function,” he said in an email.

Aerobic exercise can help older adults — even those experiencing mild memory problems — who want to protect their memory and thinking as they age, Thomas said. People at higher risk for Alzheimer’s disease can still do something about it by adding aerobic exercise to their lifestyle, he said.

In a third study of aerobic exercise, Canadian researchers studied 206 adults, average age 66, who didn’t get much physical activity and who had no history of heart or memory problems.

The participants were enrolled in a supervised six-month aerobic exercise program held three days a week and were also given thinking and memory tests and brain scans. One limitation to this study, published in Neurology in 2020: There was no control group that was not exercising, or exercising at a low intensity, with which the aerobic group’s results could be compared.

After six months of exercise, participants improved by nearly 6 percent on tests that measured executive function (the ability to plan, organize and manage time) and 2.4 percent on tests of verbal fluency — for example, reciting words beginning with a given letter in a limited amount of time.

“This change in verbal fluency is what you’d expect to see in someone five years younger,” study author Marc Poulin of the Cumming School of Medicine at the University of Calgary in Alberta, Canada, said in a statement. Participants’ blood flow to the brain also increased, ultrasound scans showed, which suggests that aerobic exercise may be linked to improvements in memory and mental acuity, according to Poulin. The results, he said, show that “even if you start an exercise program later in life, the benefit to your brain may be immense.”

What you should know:

• What makes an exercise aerobic? According to the American Heart Association, aerobic exercise involves “activities that increase your breathing and heart rate, such as walking, jogging, swimming, biking and jumping rope.” You can monitor how hard you’re working during exercise by keeping track of your heart rate — the number of times your heart beats per minute. As a general guide, the heart association says that the average person’s target heart rate during vigorous aerobic exercise should be 70 to 85 percent of the maximum recommended rate for their age, and 50 to 70 percent during moderate-intensity activities. Learn more by checking out the association’s chart of ages and heart rates.
• What are examples of aerobic exercise I can do on my own? In the study Thomas coauthored, participants could perform any exercise as long as they maintained their heart rate in the prescribed range. Most either jogged or did brisk walking, including intervals of brisk uphill walking to boost their rate. Tennis, aerobic dance classes such as Zumba, and bicycling or spin classes are other possible aerobic choices. Aim to get at least 150 minutes of moderate-intensity physical activity (such as gardening or ballroom dancing) or 75 minutes of vigorous aerobic activity (like running or swimming laps) or a combination of both each week, according to the Centers for Disease Control and Prevention.
• What if I’m not very active now? Physical activity is a key part of healthy aging, but it’s important to check with your doctor before starting any new exercise plan. The National Institute on Aging, which funds a wide range of studies on exercise and brain health, has created a list of four questions you can ask your doctor about exercise.