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How exercise improves brain aging

Exercise can change the way crucial parts of our brains communicate as we age, improving aspects of thinking and memory, according to a fascinating new study on brain aging and aerobic training. The study, which involved older African Americans, found that unconnected parts of the brain’s memory center begin to interact in complex and healthier ways after regular exercise, thereby improving memory function.

The findings expand our understanding of how movement shapes thinking and also underscore the importance of staying active, regardless of our age.

The idea that physical activity improves brain health is now well established. Experiments involving animals and people show that exercise increases neurons in the hippocampus, which is essential for the creation and storage of memory, while improving thinking skills. In older people, regular physical activity helps slow the usual loss of brain volume, which can help prevent age-related memory loss and possibly reduce the risk of dementia.

There have also been indications that exercise may change the way that distant parts of the brain talk to each other. In a 2016 MRI study, for example, researchers found that disparate parts of the brain lit up at the same time in college runners, but less so in sedentary students. This paired brain activity is believed to be a form of communication, allowing certain parts of the brain to work together and improve thinking skills, even if they don’t share a physical connection. In runners, the synchronized portions were about attention, decision-making, and working memory, suggesting that running and fitness might have helped build spirits.

But these students were young and healthy, facing an imminent threat of memory loss. It was not yet clear if and how exercise could alter the communication systems of older, squeaky brains and what effects, if any, the rewiring would have on thinking.

So for the new study, which was published in January in Neurobiology of Learning and Memory, Mark Gluck, professor of neuroscience at Rutgers University in Newark, NJ, and his colleagues decided to see what was going on in the brain. and the minds of many older people. people if they started training.

In particular, he wonders about their medial temporal lobes. This part of the brain contains the hippocampus and is the nucleus of our memory center. Unfortunately, its internal workings often start to sizzle with age, leading to a decline in thinking and memory. But Dr. Gluck suspected that this exercise could alter that trajectory.

As director of the Aging & Brain Health Alliance at Rutgers, he was already leading an ongoing exercise experiment. Working with local churches and community centers, he and his associates had previously recruited sedentary and older African American men and women from the Newark area. The volunteers, most in their 60s, visited Dr. Gluck’s lab to check their health and fitness, as well as cognitive tests. A few have also agreed to have their brain activity scanned.

Some then started training, while others chose to be a sedentary control group. All shared a similar fitness and memory function at the start. The exercise group took hour-long aerobic dance classes twice a week at a church or community center for 20 weeks.

Now, Dr Gluck and his research associate Neha Sinha, along with other colleagues, have invited 34 of those volunteers who had previously had a brain scan to come back for another. Seventeen of them had exercised in the meantime; the rest had not. The groups also repeated the cognitive tests.

Then the scientists started to compare and quickly noticed subtle differences in how practitioners’ brains work. Their scans showed more synchronized activity across their medial temporal lobes than among the sedentary group, and this activity was more dynamic. Parts of users’ lobes would light up together, then, within seconds, realign and light up with other sections of the lobe. Such promiscuous timing indicates a kind of youthful flexibility in the brain, Dr. Gluck says, as if the circuits are smoothly exchanging dance partners at a ball. The practitioners’ brains would “flexibly rearrange their connections,” he said, in a way that the brain of the sedentary group could not.

Equally important, these changes have taken place in people’s thinking and memories. Users performed better than before when testing their ability to learn and retain information and apply it logically in new situations. This type of agile thinking involves the medial temporal lobe, says Dr. Gluck, and tends to decrease with age. But the older practitioners scored higher than they started out with, and those whose brains exhibited the most new interconnections have now outperformed the rest.

That study involved older African Americans, a group that is underrepresented in health research but may not be representative of all aging people. Yet even with this caveat, “it seems that neural flexibility” gained by exercising several times a week “leads directly to memory flexibility,” says Dr. Gluck.

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