Exercise may help to keep the brain robust in people who have an increased risk of developing Alzheimer’s disease, according to a new study. The findings suggests that even moderate amounts of physical activity may help to slow the progression of one of the most dreaded diseases of aging.
For the new study, which was published in May in Frontiers in Aging Neuroscience, researchers at the Cleveland Clinic in Ohio recruited almost 100 older men and women, aged 65 to 89, many of whom had a family history of Alzheimer’s disease.
Alzheimer’s disease, characterised by a gradual and then quickening loss of memory and cognitive functioning, can strike anyone. But scientists have discovered that people who harbour a specific variant of a gene, known as the APOE epsilon4 allele or the e4 gene for short, have a substantially increased risk of developing the disease.
Genetic testing among the volunteers in the new study determined that about half of the group carried the e4 gene, although, at the start of the study, none showed signs of memory loss beyond what would be normal for their age. Then the scientists set out to more closely examine their volunteers’ brains.
For some time, researchers have suspected that the disease silently accelerates the atrophy of the hippocampus — a portion of the brain critical for memory processing. Brain scans of people who have Alzheimer’s show that their hippocampi are considerably more shrunken than those of people of the same age without the disease.
There’s been less study, though, of possible shrinkage in the brains of cognitively normal people at risk for Alzheimer’s. One reason is that, until recently, few interventions, including drugs, had shown much promise in slowing the disease’s progression.
But then some studies began to suggest that exercise might affect the disease’s progression. A 2011 brain scan study, for instance, conducted by some of the same researchers from the Cleveland Clinic, found that elderly people with the e4 gene who exercised regularly had significantly more brain activity during cognitive tests than people with the e4 gene who did not exercise. But could exercise also be affecting the physical shape of the brain, the researchers wondered, particularly in people with the e4 gene?
To find out, they asked the volunteers in their new experiment how often and intensely they exercised. About half, as it turned out, didn’t move much at all. But the other half walked, jogged or otherwise exercised