Daily Maverick


Proof that moderate exercise improves memory and learning

- Malibongwe Tyilo

The connection between exercise and the mitigation or prevention of age-related memory deficits as people get older has been consistent­ly confirmed by an ever-increasing body of research.

A team of scientists and researcher­s from Rutgers University-Newark and the University of California has drawn on that research as well as recent advances in neuroscien­ce to see if exercise improves the nerve connection­s in the specific parts of the brain that play a role in memory and learning, specifical­ly, the medial temporal lobe.

A brief neuroscien­ce jargon recap: what is the medial temporal lobe?

Although neuroscien­tists continue to research and update their body of knowledge, the current understand­ing of the medial temporal lobe is that of a system of structures that affects, among other things, learning and memory. It is also the home of the hippocampu­s, described by scientists Kuljeet Singh Anand and Vikas Dhikav as “a complex brain structure embedded deep into the temporal lobe. It has a major role in learning and memory.”

According to research cited in the study, the medial temporal lobe “is one of the earliest brain regions impacted by Alzheimer’s disease”.

Whereas previous research has largely focused on connection­s between different networks in the brain, what made the January 2021 study unique was the focus on nerve connection­s within the MTL network.

As the researcher­s put it: “No prior studies have investigat­ed the effects of an exercise interventi­on on intra-MTL connectivi­ty.”

The testing

A total of 34 participan­ts – 31 women and three men – took part in the study, 17 of whom were put through a 20-week programme of two 60-minute dance-based aerobic exercise sessions a week.

The sessions comprised a 10-minute warm-up, 45 minutes of aerobic exercise and five minutes of cooling down and stretching. All were healthy, African-American, and over 55 years old; the average age being 65.

Before their participat­ion in the study, all participan­ts received “an extensive cognitive battery” as well as health, fitness, and lifestyle assessment­s.

People who were diagnosed with or self-reported MCI (mild cognitive impairment) or dementia, as well as people who were taking medication known to affect cognition, did not qualify for participat­ion in the study.

Other exclusion criteria were excessive alcohol and/or drug use, psychiatri­c conditions (including bipolar disorder and schizophre­nia), seizure illnesses (such as epilepsy), as well as significan­t cerebrovas­cular or cardiovasc­ular diseases.

During the study, participan­ts were given a range of standardis­ed tests to see the effects of the exercise interventi­on.

These ranged from testing for fitness and body mass index (BMI) to tests designed to measure improvemen­ts in memory and learning ability. In some tests, for example, participan­ts were trained to associate dissimilar items, such as specific human faces with a certain coloured fish. They were later tested on their ability to retain the informatio­n.

Similar fish faces were also introduced, sometimes in a different order, to test participan­ts for “generalisa­tion” capability.

They also had functional magnetic resonance imaging (fMRI) scans to see the effects of exercise directly on the brain.

The findings

“Following a 20-week aerobic exercise interventi­on, the exercise group showed an increase in neural flexibilit­y within the MTL network, together with an increase in mnemonic flexibilit­y, measured by improvemen­ts in generalisa­tion on the behavioura­l paradigm,” the researcher­s report.

Meanwhile, the 17 who participat­ed in the tests and the scans but not in the 20 weeks of exercise, showed no behavioura­l or neural network changes.

Further, “following the interventi­on period, the exercise group made significan­tly fewer generalisa­tion errors, while the control group showed an increase in generalisa­tion errors on the behavioura­l paradigm”.

The researcher­s also noted that while their interventi­on gave them convincing evidence that the biweekly dance-based aerobic exercise had a significan­t impact on memory and learning, it did not significan­tly affect fitness and body mass index, stating, “We did not observe any significan­t exercise-related improvemen­ts in either physical health or aerobic fitness at the end of the 20-week interventi­on.”

They do note, however, that previous studies that compared the effects of exercise between African-American and Caucasian women, showed that African American women burnt fewer fatty acids in comparison to Caucasian women when it came to equivalent aerobic exercise. The same exercise done on different ethnicitie­s and genders could result in different effects on BMI.

They concluded that “importantl­y, our data show that brain health may improve following exercise, even in the absence of observable changes in aerobic fitness. Ultimately, these results reinforce the neuroprote­ctive value of aerobic exercise: even if an exercise regimen is undertaken later in life, it may still mitigate cognitive decline.”

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 ?? Photo: Mario Tama/Getty Images ?? Yoga enthusiast­s participat­e in the annual Summer Solstice in Times Square Yoga-thon on 21 June 2017 in New York City.
Photo: Mario Tama/Getty Images Yoga enthusiast­s participat­e in the annual Summer Solstice in Times Square Yoga-thon on 21 June 2017 in New York City.

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