The U.S. population is aging, and more people than ever are experiencing a natural waning of cognitive function.
But a new study in the journal JAMA suggests two candidates for slowing that decline — exercise and meditation — might not help after all.
The randomized clinical trial involved 585 seniors with concerns about their own cognitive abilities, but no dementia diagnosis.
“They focused on that group of people because they thought they might be more at risk for dementia along the line, as opposed to those that don't feel like they have any cognitive concerns,” said cognitive aging expert Dr. Helena Blumen of the Albert Einstein College of Medicine.
Compared to a control group who received only health education, the researchers found no mental benefits from an hour a day of mindfulness-based stress reduction; 300 minutes per week of aerobic, strength and functional exercise; or a mix of the two.
Blumen, who did not work on the study, said the results didn’t surprise her.
“I know some people are,” she said. “But I think previous studies have at best shown modest benefits from exercise on cognition.”
Still, she thinks it’s too early to throw in the gym towel.
Other studies do show mental benefits of exercise combined with factors like diet and social interaction, so more research is needed.
“Do we have to add something to the exercise to see improvements in cognition?” said Blumen. “Because there's a lot of epidemiological studies showing that people who exercise more do do better. So we just have to figure out how we can develop interventions that can pick up on that.”
The subjects ranged in age from 65-84 and made up two populations: One at Washington University in St Louis, the other at University of California, San Diego.
Researcher’s looked for improvements in episodic memory — the retention of autobiographical events, as opposed to skills — and executive function — a catch-all term for higher processes used for activities like planning, reasoning and problem-solving.
Using MRI, they also screened for changes in brain areas expected to reflect those changes, including the hippocampus — which plays key roles in emotion, episodic memory and the autonomic nervous system — and the dorsolateral prefrontal cortex, which plays a key role in higher cognitive functions like attention and working memory.
They saw no significant changes in either.
Moreover, because the study overwhelmingly comprised white, female, college-educated people, its representativeness of the aging population at large is limited.
Despite its limitations, Blumen said it was a good study.
“I thought it was a very well-designed study, well-executed in a large group of older adults with subjective cognitive concerns,” she said “So, in terms of that, I was very happy to see a study like that.”
