DALLAS, Texas — Your exercise calendar may say it’s “leg day” but researchers find working out is also helping your brain. A team from UT Southwestern says blood flow increases to the brain during exercise, just like other body parts. Their study points to this effect possibly protecting older adults from memory loss and the onset of dementia.
“This is part of a growing body of evidence linking exercise with brain health,” says study leader and professor of neurology Rong Zhang, Ph.D., in a university release. “We’ve shown for the first time in a randomized trial in these older adults that exercise gets more blood flowing to your brain.”
Study authors add one in five people over age 65 deal with some form of mild cognitive impairment (MCI). These small changes in brain function can impact memory, decision-making, and even reasoning skills. For many seniors, MCI is the first sign that they’re developing a form of dementia — such as Alzheimer’s disease.
How does blood flow connect to brain health?
Previous studies have discovered that less blood flow to the brain has a connection to MCI and dementia risk. Stiffer blood vessels traveling to the brain also impact cognitive performance. These studies also show that aerobic exercise can help boost brain function and memory in some healthy seniors. Unfortunately, these reports could not find a direct link between exercise, stiffer blood vessels, and blood flow.
“There is still a lot we don’t know about the effects of exercise on cognitive decline later in life,” adds professor of psychiatry C. Munro Cullum, Ph.D. “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.”
The new study examined 70 adults between 55 and 80 years-old already dealing with MCI. The group underwent a full cognitive exam, fitness tests, and MRI scans before starting a one-year exercise experiment. Researchers randomly assigned each of the older men and women to a moderate aerobic exercise program or a stretching program.
For the group doing aerobic exercise, they worked out three to five times a week for 30 to 40 minutes. These sessions could even be as simple as a brisk walk. Exercise physiologists monitored both groups for about six weeks before having the participants track their own progress using a heart rate monitor.
Discovering new clues to better brain health
Out of the 70 participants at the start, 48 completed the year-long program and returned for follow-up tests. Only 19 from the aerobic exercise group finished the experiment, the other 29 had spent the year stretching.
For those making it through all the exercise however, researchers discovered less stiffness in the blood vessels in their necks. The team also detected increased overall blood flow to the aerobic exercise group’s brains. Additionally, the more oxygen consumption increased, the greater the changes in brain blood flow and stiffness became.
Oxygen consumption is one of the key markers of aerobic fitness. Unfortunately, the same changes did not appear in the group only following a stretching program for one year.
So can exercise really fight off dementia?
Although the results reveal healthier blood flow to the brain, researchers did not find major changes in cognitive function. However, the team says this may have to do with the small size of their trial group.
Study authors believe that blood flow changes may precede memory and brain function issues. To see the long-term impact of exercise on cognitive decline, the team is now conducting a two-year study called Risk Reduction for Alzheimer’s Disease (rrAD).
“There are likely some people who benefit more from exercise than others,” Cullum explains. “But with the sample size in this study, it was hard to analyze subgroups of people to make those conclusions.”
“Having physiological findings like this can also be useful for physicians when they talk to their patients about the benefits of exercise,” Zhang concludes. “We now know, based on a randomized, controlled trial, that exercise can increase blood flow to the brain, which is a good thing.”
The study appears in the Journal of Alzheimer’s Disease.