Even simple exercise may help aging brain, study hints [Video]

New research suggests that even a simple exercise routine could help older Americans with mild memory problems.

Doctors have long advised physical activity to keep a healthy brain fit. But the government-funded study marks the longest test of whether exercise makes any difference once memory starts to slide — research conducted during a pandemic that added isolation to the list of risks to participants’ brain health.

Researchers recruited about 300 sedentary older adults with hard-to-recognize memory changes called mild cognitive impairment, or MCI — a condition that is sometimes, but not always, a precursor to Alzheimer’s disease. Half were assigned aerobic exercises and the rest were given stretches and balance movements that only moderately increased their heart rate.

Another key piece: Participants in both groups were showered with attention from trainers who worked with them at YMCAs across the country — and when COVID-19 closed gyms, they helped them keep exercising at home via video calls.

Related video: Exercising more than the recommended amount lowers the risk of death

After a year, cognitive tests showed that neither group had deteriorated, said lead researcher Laura Baker, a neuroscientist at the Wake Forest School of Medicine. Nor did brain scans show the shrinkage associated with worsening memory problems, she said.

In comparison, similar MCI patients in another long-term brain health study — but without exercise — experienced significant cognitive decline over a year.

Those early findings are surprising, and the National Institute on Aging warned that tracking non-athletes in the same study would have provided better evidence.

But the results suggest “this is doable for everyone” — not just seniors who are healthy enough to work up a sweat, said Baker, who presented the data Tuesday at the Alzheimer’s Association International Conference. “Exercise should be part of prevention strategies” for seniors at risk.

Past research has shown that regular physical activity of any kind can reduce harmful inflammation and increase blood flow to the brain, said Maria Carrillo, senior research associate at the Alzheimer’s Association.

But the new study is especially intriguing because the pandemic struck halfway through, leaving already vulnerable seniors socially isolated — something that has long been known to increase people’s risk of memory problems, Carrillo said.

It’s a frustrating time for dementia research. Doctors are hesitant to prescribe a new expensive drug called Aduhelm that could be the first to slow the progression of Alzheimer’s disease, but it’s not clear yet if it really helps patients. Researchers reported last month that another drug that works in the same way — by targeting amyloid plaques that are a hallmark of Alzheimer’s — failed in a key study.

While amyloid clearly plays a role, it’s important that drugmakers increasingly target many other factors that can lead to dementia, Carrillo said, because effective treatment or prevention likely requires a combination of customized strategies.

An example of a new approach: Sometimes in dementia the brain has trouble processing blood sugar and fats for the energy it needs, John Didsbury of T3D Therapeutics told the Alzheimer’s meeting. His company is testing a pill that aims to increase that metabolism, with results expected next year.

Meanwhile, the urgency to explore whether steps people can take today — such as exercise — can provide at least some protection.

How much and what kind of movement? In Baker’s study, seniors were required to exercise for 30 to 45 minutes four times a week, whether it was a brisk spin on the treadmill or the stretching exercises. That’s a big question from anyone who is sedentary, but Baker said MCI’s effects on the brain make it even harder for people to plan and maintain the new activity.

Hence the social stimulation – which she attributed to the fact that each participant had more than 100 hours of physical activity. Baker suspects the sheer volume could explain why even simple stretching provided a clear advantage. Participants would have to exercise for another six months without formal support, data Baker has not yet analyzed.

“We wouldn’t have done the exercise alone,” said retired agricultural researcher Doug Maxwell of Verona, Wisconsin, who took part in the study with his wife.

The duo, both 81, were both assigned to the stretching classes. They felt so good afterward that, when the study ended, they bought electric bikes in hopes of even more activity — efforts Maxwell acknowledged are hard to keep track of.

Next: Baker is leading an even larger study of older adults to see if adding exercise to other steps that don’t hurt, such as a heart-healthy diet, brain games and social stimulation can combine to reduce dementia risk.


The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

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