WASHINGTON.- El physical exercise and the meditation practice do not improve health older adults brainaccording to a surprising new study published this week by the scientific journal JAMA. The experiment involved 580 older adults of both sexes, and its objective was to analyze whether a routine of physical exercise, meditation practice, or both, enhanced their cognitive abilities and memory, or if it modified the structure of their brains in any way.
“We thought we were going to find benefits with the practice of physical exercise or meditation, and especially with the combination of both,” says Eric Lenze, head of the Department of Psychiatry at the Washington School of Medicine in St. Louis, director of the new study.
“But no,” Lenze points out with some disappointment.
The results seem question the ability of physical exercise and other lifestyle changes to combat cognitive aging as a result of age. But it also raises a new question: Do we know enough regarding the brain and mind, or regarding how to study them, to determine whether we can modify them with physical exercise or meditation?
“Given that other studies have found a significant relationship between meditation, physical exercise and mental health, how do you explain these new results?” asks Art Kramer, director of the Center for Brain and Cognitive Health at Northwestern University in Boston, which has extensively researched the relationship between exercise and brain health, but was not involved in the new study.
The answers might have implications for anyone hoping to stay physically active in order to stay mentally sharp well past middle age.
Indeed, there is a great deal of past research suggesting that our lifestyle influences the health of our brain. Physical exercise in particular seemed to play a crucial role in memory and cognitive ability in old age. A review of previous studies conducted in 2011 concluded that “There is growing evidence that both aerobic exercise and resistance training are important for maintaining brain and cognitive health in old age”.
As confirmation of that claim, a famous 2011 study of 120 older men and women revealed that Those who started some moderate exercise routine —in most cases, walks— improved their performance in memory tests and they developed a larger hippocampus, an area of the brain that is crucial for memory function. In contrast, sedentary participants in the control group experienced reduced hippocampal volume and impaired memory.
Similarly, meditation has also been associated with improvements in some aspects of memory and thinking in older adults, presumably because it helps reduce stress and distractions.
But much of these investigations were short-term or carried out on very small groups of just a couple of dozen participantsor were epidemiological in nature, meaning they found suggestive links between physical activity, meditation, and mental health, but did not show that this directly benefited people’s brains.
That’s why this new study is so remarkable. It started in 2015, when its authors —scientists from the University of Washington or the University of California at San Diego— recruited 585 healthy but sedentary men and women between the ages of 65 and 84. None of the participants had been diagnosed with dementia, but they expressed concern that their thoughts and memories were less clear than before.
The scientists tested the cognitive abilities of all of them, focusing on attention, working memory and recall of words or images, and also scanned the volume of their hippocampus. They then randomly divided them into several groups. One group began physical exercise twice a week in supervised 90-minute classes, alternating between walking or similar aerobic activities, light weight training, and balance practice. After six months, they took their routines home, working out on their own for regarding an hour a day for another year.
A second group learned to reduce stress with a technique known as “mindfulness” or mindfulness, which combines meditation, yoga, and mental exercises, and he practiced it under supervision for six months and on his own for the next year. A third group exercised and meditated several times a week, while the control group attended healthy living classes twice a week.
After six months and once more following 18 months, the researchers repeated the cognitive tests and brain imaging studies.
At the end of the experiment, Hippocampal volume was reduced in nearly all participants, whether they exercised, meditated, or neither.
At the same time, their performance on cognitive tests had increased slightly, a universal but misleading improvement, Lenze says. If exercise or meditation had actually benefited the brains of these people, their scores should have been higher than those of the control group. But they weren’t, so Lenze and his colleagues concluded that any improvement was simply because “by repeating the tests, people get better and better.”
Do the results reveal that exercise and meditation are pointless for brain health?
“What this study tells us is that we don’t know as much regarding the brain as we think,” says Lenze.
Exercise and meditation did not improve certain cognitive tasks tested in this study, the researcher says, but they might contribute to other thinking functions, or perhaps their effects would be different in people with greater or lesser previous memory problems.
“I think the authors did a very rigorous study,” says Teresa Liu-Ambrose, director of the Center for Brain Health at the University of British Columbia in Vancouver, who studies the relationship between exercise and the brain but was not involved in the study. this investigation.
But Liu-Ambrose too questions the narrowness of the specific tests and analyzes used to measure changes in participants’ cognitive abilities.
Adding to his criticism is Mark Gluck, a professor at the Center for Molecular and Behavioral Neuroscience at Rutgers University in Newark. “Had the researchers used more sensitive behavioral measures of these people’s thinking acuity and memory, the results might have been very different,” he notes.
Gluck adds that other types of brain imaging studies might also have detected significant changes within people’s brains at the end of the experiment.
Overall, the results of the new study are relevant “because they suggest that future research should carefully consider the characteristics and composition of the participant groups” and the exercise and meditation routines used, “to resolve the ambiguity” regarding whether these practices have some impact on brain aging.
According to Lenze, what the result definitely does not suggest is that exercise or meditation is useless. “We don’t want people to get the message that physical activity is useless.”
Both exercise and meditation are still helpful, says Lenza, who practices both.
“There is a lot that we still have to learn regarding the brain,” says the researcher.
By Gretchen Reynolds
(Translation by Jaime Arrambide)
