Brain Scans Show Exercisers Have Less Alzheimer's-Associated Plaque
A recent study using PET and MR images showed that people who said they exercised five times a week in late middle age did better on cognitive tests and showed less accumulation of the beta amyloid plaque, the protein that builds up in the brains of people with Alzheimer's disease.
The study, conducted by researchers from the University of Wisconsin School of Medicine and Public Health, examined 317 people enrolled in the Wisconsin Registry for Alzheimer's Prevention (WRAP), which is a longitudinal study that is tracking 1,500 people who enrolled as middle-aged adults with no cognitive problems.
About three-quarters of those in WRAP have a family history of Alzheimer's disease, which increases their own risk of developing it.
The 317 people in the exercise study were divided into 79 inactive people and 238 active people, based on whether their total physical activity score met the American Heart Association guideline of at least 30 minutes of moderate intensity physical activity at least five times a week.
Their brains were imaged using PET and MRI technology, and they were given an array of cognitive tests.
Researchers found that age itself—rather than having a family history or a gene associated with Alzheimer's disease—was the greatest predictor of whether people had begun developing the biomarker changes associated with the disease.
However, at every age, active people did better on immediate memory and visual spatial tests, and had less amyloid plaque, better brain glucose metabolism, and higher hippocampus volume compared to inactive people.
In addition, the inactive group had more mild depression, higher body weight, lower higher-density lipoprotein levels, and more glucose intolerance. Therefore, researchers controlled for these potentially confounding factors in their analyses.
"This is the first time we've shown, in a group of late middle-aged adults who are at-risk for Alzheimer's disease, that exercise can hold off the age-related changes associated with the disease pathology," says Ozioma Okonkwo, PhD, an assistant professor of medicine at the School of Medicine and Public Health.
"This is an observational trial, so it would be great to follow it with a controlled trial in which people were randomly assigned to different intensity levels of exercise," Okonkwo says. "If a controlled trial showed the same results, it would be compelling evidence for exercise as a way to hold off Alzheimer's disease, particularly for people with a higher risk for it."
The study was published in the journal Neurology.
— SOURCE: University of Wisconsin-Madison
