Proof that moderate exercise improves memory and learning
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.”
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.
“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.”