Boosting Blood Flow May Help Protect Memory

Aerobic exercise — the kind that makes you breathe harder and gets your heart pumping out more oxygen-carrying blood with every beat — may play an important role in improving your thinking and memory skills.

Two studies suggest that participants who did aerobic exercise several times a week for several months performed better on certain mental tests. Brain scans taken at the beginning and end of each study also showed blood flow to the brain had increased.

What studies like these suggest is that increased blood flow from aerobic exercise is linked to reduced risk of memory loss, said Binu Thomas, a senior researcher in neuroimaging at the University of Texas Southwestern Medical Center and coauthor of one of the studies. “By adding as little as four weeks of exercise, you start seeing cardiorespiratory fitness improvement, which is definitely beneficial for brain function.”

Even for those whose memory has started to fade and are at higher risk for Alzheimer’s disease, they can still do something about it by adding aerobic exercise to their lifestyle, he said.

In the University of Texas study, published in the Journal of Alzheimer’s Disease, Thomas and his colleagues studied 30 participants, age 60 or older, with mild memory problems. Half underwent 12 months of aerobic exercise training — meaning exercise that significantly raised their heart rate — while the rest did only stretching.

In both groups, each participant was trained and supervised individually, to avoid any group social influence during training. Participants did their activity — either aerobic exercise or stretching — three times a week for 25 to 30 minutes in the beginning, eventually increasing to four to five times a week for 30 to 40 minutes.

The researchers used brain scans to map changes in blood flow after a year of aerobic workouts. They found that exercise improved blood flow to two key regions of the brain associated with memory.

The exercise group also showed a 47 percent improvement in some memory scores after a year, compared with minimal change in the stretching group, researchers reported.

Although the study participants already had mild memory problems, Thomas said this type of exercise should also help older adults who want to protect against slowed memory and thinking as they age. “If they were to perform exercise for one year, I would expect similar benefits in brain function,” he said in an email.

In a second study looking at the benefits 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, plus did one workout on their own once a week. Exercise sessions increased from 20 minutes to 40 minutes as the study progressed. Participants were also given thinking and memory tests and brain scans at the beginning and end of the study to assess changes.

The researchers found that after six months of exercise, participants improved by nearly 6 percent on tests of what researchers call executive function (the ability to do things like plan, organize and manage time) and 2.4 percent on tests of how quickly they can produce certain information — for example, reciting words beginning with a given letter in a limited amount of time.

The results, study author Marc Poulin of the Cumming School of Medicine at the University of Calgary in Alberta, Canada, said in a statement, showed that “even if you start an exercise program later in life, the benefit to you brain may be immense.”

“This change in verbal fluency is what you’d expect to see in someone five years younger,” Poulin said.

In addition, 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, he said.

One limitation to this study: 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. 

The study was published in Neurology, the medical journal of the American Academy of Neurology.

What you should know:

• What makes an exercise aerobic? Senior researcher Binu Thomas of the University of Texas Southwestern Medical Center says aerobic exercise should raise your heart rate to at least 75 to 85 percent of the maximum recommended rate for your age. For example, according to the American Heart Association, someone age 65 should have a maximum heart rate of 155, meaning their target heart rate during exercise should be from 116 to 132. The American Heart Association has a chart of ages and heart rates.
  
  
• What are some examples of aerobic exercise I can do on my own? In the University of Texas study, Thomas said 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. Swimming, aerobic dance classes, such as Zumba, and bicycling or spin classes are other possible aerobic choices.
  
  
• What if I’m not very active now? Physical activity is an important 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, also has a number of tips on fitting exercise into your daily life and ways to safely get more active.