Scientists Work Out How Exercise Saves Your Brain

By Dennis Thompson, HealthDay reporter >

Monday, January 10, 2022 — Exercise helps you stay fit and healthy, and researchers say it may also help you stave off dementia and Alzheimer’s disease. Now they have a better understanding of the hidden benefits that help the brain.

A new study reports that older people who are more physically active have higher levels of a protein that promotes better communication between synapses in the brain.

said lead researcher Kaitlin Casaletto, an assistant professor of neuroscience at the University of California, San Francisco. “All of our thinking and memory happens as a result of these synaptic connections.”

The researchers found that even people in their 80s and 90s whose brains were full of amyloid plaques and tau tangles — hallmarks of Alzheimer’s disease — had higher levels of these tangled proteins if they were more active.

Synaptic proteins are involved in the production and release of neurotransmitters, Casalito said, the biochemicals in the brain that promote communication between neurons.

“We think that having more of these proteins indicates that maybe you have more synapses and/or maybe your synapses are working a little bit better,” Casalito said. “You get more of that juice into the brain and it makes connections easier.”

This study involved more than 400 older adults who agreed to wear monitors that tracked their daily physical activity. They were all involved in the Rush University Memory and Aging Project, a long-term effort to identify the causes of Alzheimer’s disease and dementia.

Indeed, Casaleto said, researchers have found that people in this group who have higher levels of physical activity also tend to have better cognitive performance and a lower risk of dementia.

The next step was to find out why. Brain autopsies provided answers.

“We followed these adults to death. They donated their brains to the autopsy program and we were able to examine brain tissue after death,” Casalito said. The mean age of death among participants was 90.

Researchers said autopsies revealed higher levels of synaptic proteins in the brains of those who tend to move around more during their daily lives.

“We saw a beautiful linear relationship,” Casalito said. “The more activity, the higher the synaptic protein levels. To me, that indicates the importance of each movement.”

These levels were high even among people who had physical evidence of Alzheimer’s disease in their brains.

“The aging brain’s ability to promote this healthy response to activity may help counteract age-related brain changes and help enhance cognition,” Casalito said.

Furthermore, the researchers found these elevated levels of synaptic proteins in six areas of the brain — not only in the memory center, but in other parts related to thought and reasoning as well.

“It suggests that it’s a whole-brain phenomenon,” Casalito said.

In background notes, the researchers said that as people age, their brains tend to accumulate toxic proteins such as amyloid beta and tau. Since these proteins form clumps and tangles, they can interfere with synaptic communication between neurons and eventually cause synapses and neurons to disintegrate.

Heather Snyder, vice president of medical and scientific relations at the Alzheimer’s Association, said the findings suggest that physical activity can enhance flexibility in the brain.

The continuous influx of neurotransmitters from these proteins may improve synaptic function of aging brains, maintaining communication between neurons despite interference caused by toxic amyloid and tau.

“If you can keep your brain cells healthy and communicating for longer, you might slow the changes you might see in disease or you might be able to reduce the brain’s exposure to further injury or other insults,” Snyder said.

Casalito said the study didn’t measure the strength of each person’s physical activity, just how much they tend to move during the day.

Snyder said there are a number of activities you can do to boost brain health, such as ballroom dancing, walking the neighborhood or riding a stationary bike at home.

“Find something you will enjoy, stick with and keep doing,” Snyder said, adding that seniors should check with their doctor before undertaking a new activity.

The new study was published Jan. 7 in Alzheimer’s and Dementia: Journal of the Alzheimer’s Association.


  • Caitlin Casalito, Ph.D., Assistant Professor, Neurology, University of California, San Francisco
  • Heather Snyder, Ph.D., Vice President, Medical and Scientific Relations, Alzheimer’s Association
  • Alzheimer’s and[رسقوو]
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  • Dementia: Journal of the Alzheimer’s Association, January 7, 2022

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