Exercise can help older people preserve their memories

Combining data from dozens of experiments allows researchers to show whose brains benefit most from exercise.

We all know that exercise is good for us, but it still leaves a lot of questions. How many exercises? Who benefits more? And if in our lives? A new study by psychologists at the University of Pittsburgh combines data from dozens of studies to answer these questions, showing that older people can prevent a decline in certain types of memory by following regular exercise.

“Everyone always asks,‘ How much should I do? What is the minimum for improvement? ‘ Said lead author Sarah Agjayan, a student of clinical and biological health psychology at the Kenneth P. Dietrich School of Arts and Sciences. “From our study, it seems that exercise about three times a week for at least four months is what you need to get fruit in episodic memory.”

Episodic memory is a type that deals with events that have happened to you in the past. It is also one of the first to decline with age. “I usually like to talk about how you first got behind the wheel of a car,” Agjayan said. “So you can remember where you were, how old you were, who was in the passenger seat and explained to you everything, that feeling of excitement.”

Exercises that stimulate the heartbeat have shown promising effects on improving brain health, and experiments on mice have shown that they improve memory – but studies looking at the same relationship in humans have been mixed.

Seeking clarity in the murky waters of the scientific literature, the team analyzed 1,279 studies, eventually narrowing them down to 36 that met certain criteria. They then used specialized software and a considerable number of Excel spreadsheets to convert the data into a form in which one could directly compare different studies.

This work paid off when they found that combining these 36 studies was enough to show that for older people, exercise can really benefit their memory. The team, including Agjayan adviser Kirk Erickson from the Department of Psychology and other researchers from Pete, Carnegie Mellon University and[{” attribute=””>University of Iowa, published their results in the journal Communications Medicine on February 17, 2022.

Past analyses looking at connections between exercise and memory didn’t find one, but Aghjayan and her team took several extra steps to give them the best chance of finding a link if one did exist. They limited their search to particular groups and age brackets as well as a specific kind of rigorous experimental setup. Another key was focusing specifically on episodic memory, which is supported by a part of the brain that’s known to benefit from exercise.

“When we combine and merge all this data, it allows us to examine almost 3,000 participants,” Aghjayan said. “Each individual study is very important: They all contribute to science in a meaningful way.” Individual studies, however, may fail to find patterns that actually exist because of a lack of resources to run a big enough experiment. The studies individually couldn’t find a link between exercise and memory — it took looking at the whole body of research to bring the pattern into focus.

With that much larger pool of participants, the team was able to show a link between exercise and episodic memory, but also was able to start to answer more specific questions about who benefits and how.

“We found that there were greater improvements in memory among those who are age 55 to 68 years compared to those who are 69 to 85 years old — so intervening earlier is better,” Aghjayan said. The team also found the greatest effects of exercise in those who hadn’t yet experienced any cognitive decline, and in studies where participants exercised consistently several times a week.

There are still questions left to be answered. The team’s analysis couldn’t answer how the intensity of exercise affects the memory benefits, and there’s plenty to learn about the mechanism behind the link. But the implications for public health are clear: Exercise is an accessible way older adults can stave off memory declines, benefiting themselves, their caretakers and the healthcare system, Aghjayan said.

“You just need a good pair of walking shoes, and you can get out there and move your body.”

Reference: “Aerobic exercise improves episodic memory in late adulthood: a systematic review and meta-analysis” 17 February 2022, Communications Medicine.
DOI: 10.1038/s43856-022-00079-7

The papers’ coauthors include Kirk Erickson, Chaeryon Kang, Xueping Zhou, Chelsea Stillman, Shannon Donofry, Thomas W Kamarck, Anna L Marsland and Scott H Fraundorf at the University of Pittsburgh, Themistokles Bournias at Carnegie Mellon University and Michelle Voss at the University of Iowa. Exercise can help older people preserve their memories

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