Eric Renze, director of psychiatry at the University of Washington School of Medicine, who led the new study, said: .
The results seem to cast doubt on the ability of exercise and other lifestyle changes to combat age-related cognitive decline. It raises new questions about whether we really know enough about the brain and mind, or how to study them, to know if we are altering the mind.
“If other research has found important links between mindfulness and exercise, and cognitive function and brain health, how do we explain the current results? ” Art Kramer, director of the Center for Cognition and Brain Health at Northeastern University in Boston, has studied exercise and the brain extensively, but was not involved in the new research.
The answer could have implications for all of us who expect physical activity to keep us sharp in middle age and beyond.
Previous studies have shown that exercise helps brain health
Indeed, a wealth of past research suggests that our lifestyle influences brain health. Exercise, in particular, appears to play an important role in how well we think and remember with age. There is increasing evidence that it is important for maintaining cognition and brain health in humans.”
To support that claim, a well-known 2011 study of 120 older men and women found that those who started moderate-intensity exercise (mainly walking) had better scores on memory tests and improved memory. We found that the size of the hippocampus, a part of the brain important for function, increased. People in the sedentary control group experienced a decrease in hippocampal volume and memory.
Similarly, mindfulness has been associated with improvements in some aspects of memory and thinking in older adults, possibly because it helps reduce stress and distraction.
However, many of the studies were short-term and small, probably involving dozens of participants, or epidemiological. So, while we found suggestive links between physical activity and mindfulness and mental clarity, we haven’t proven that they directly improve people’s brains.
New research on exercise, mindfulness and the brain
As such, this new study deserves attention. Starting in 2015, the authors, primarily based at the University of Washington or the University of California, San Diego, recruited 585 healthy but inactive men and women between the ages of 65 and 84. Their thinking and memory were duller than before.
The scientists tested everyone’s thinking skills, focusing on attention, working memory, word and picture recall, and also scanned the hippocampal volume and randomly assigned them to different groups. One alternated between walking or similar aerobic exercise, light weight training, and balance exercises in his twice-weekly supervised 90-minute exercise classes with her. Six months later, they brought the routine home, plus he exercised mostly on his own for about an hour each day for a year.
A second group studied a mindfulness-based stress reduction technique that combined meditation, yoga, and mental exercises under supervision for six months and then self-studyed the following year. A third group did both exercise and meditation several times a week, and a control group attended healthy living classes twice a week.
Six months later and after age 18, the researchers repeated cognitive tests and brain scans.
Ultimately, hippocampal volume decreased in almost everyone, regardless of whether they exercised or meditated.
At the same time, their cognitive scores rose slightly, a universal but misleading improvement, Lenze said. If exercise and meditation actually benefited people’s brains, their scores would have been higher than those of the control group. He believes that there is some benefit in “becoming better at receiving”.
What this means for exercisers and aging brains
So do the results show that working out and mindfulness are irrelevant for brain health?
“I think this study shows that we don’t know as much about the brain as we think,” Lenze said.
Exercise and mindfulness did not improve any specific cognitive task in this study, but they probably help with other types of thinking and may have different effects in people with more or less pre-existing memory concerns. be.
“I think the authors did a very rigorous study,” says Teresa Liu, director of the Center for Brain Health at the University of British Columbia in Vancouver, who studies exercise and the brain but was not involved in the study. – said Ambrose.
But she also questioned the narrowness of certain tests and analyzes used to measure changes in people’s thinking skills.
So did Mark Gluck, a professor of neuroscience at the Center for Molecular and Behavioral Neuroscience at Rutgers University in Newark. “If researchers had used behavioral measures that are more sensitive to how well people think and remember, the reported results might have been quite different,” he said.
Other brain-scanning techniques could have similarly identified meaningful changes in people’s brains by the end of the study, he said.
Overall, the results of the new study “importantly suggest that future studies should carefully consider the characteristics of the study population,” Kramer said.
What the findings don’t suggest is that working out or meditating is futile, Lenze said.
Exercise and mindfulness are both still beneficial, he said, and he practices both.
After all, future studies may detect benefits that weren’t seen in this experiment. “We still have a lot to learn about the brain,” he said.
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