New Insights Into How Staying Active May Delay Onset of Alzheimer’s

Treatment options for Alzheimer’s disease remain limited and largely ineffectual, and thus in the near term preventing—or at least delaying—the onset of Alzheimer’s may be the best approach to mitigate the individual and societal impact of this disorder.

Last year, the Alzheimer’s Association published the report “Changing the Trajectory of Alzheimer’s Disease: How a Treatment by 2025 Saves Lives and Dollars” that discussed this issue. It noted that if a treatment could delay Alzheimer’s by five years, it could reduce the number of people projected to have the disease in 2050 by over 40 percent, while also saving over $200 billion in health care costs. And while the news on Alzheimer’s treatments may be discouraging, research suggests that there are ample ways to reduce the risk of developing Alzheimer’s, such as keeping mentally and physically active.

“The evidence is very positive in this area,” said James Becker, M.D., a professor of psychiatry, psychology, and neurology at the University of Pittsburgh. “There are a surprising number of ways to reduce one’s risk without even leaving a chair.”

Varied activities—such as swimming, running, or golf—might be equally effective in keeping the brain healthy during aging, according to recent research by Becker and his colleagues published March 11 in the Journal of Alzheimer’s Disease.

The team made use of a range of data available from seniors who were part of the Cardiovascular Health Study. This was a decade-long observational study of risk factors related to heart disease and stroke. Participants received multiple brain scans and were asked about their current physical activity routines; a subset of the group was also given cognitive assessments. Subjects were 65 or older.

The researchers found that those people who burned the most calories—regardless of the type of physical activities they engaged in—had larger volumes in multiple brain regions associated with learning and memory (such as the frontal, temporal, and parietal lobes).

Among the participants who had cognitive evaluations, the researchers also observed that physical activity and larger brain volumes were associated with a lower risk of developing cognitive impairment or Alzheimer’s.

Becker pointed out that while the type of activity was not essential, the energy expended was. “It does seem that intensity is important, as we saw really noticeable effects only for individuals in the top 25 percent of activity levels.”

Still, Becker was encouraged that the results suggest that beginning aerobic-type activities even in older age is worthwhile.

“It doesn’t hurt at 70, but it is much better if you can start at 40 to get a larger effect over time,” he told Psychiatric News. “And I think we are coming to a point where we need to start getting this news to the internal medicine doctors so they can start leaning on their patients.”

While physical activity does appear to delay the cognitive symptoms of Alzheimer’s, a recent study from Minnesota’s Mayo Clinic published in Neurology has found that the underlying molecular aspects of Alzheimer’s may not be affected.

A team led by Prasanthi Vemuri, Ph.D., a professor of radiology, took brain images of 393 senior adults (aged 70 and over) that looked specifically at the levels of amyloid protein—whose buildup is associated with Alzheimer’s—over time.

They observed that lifestyle enrichment (keeping mentally and/or physically active) during middle age (ages 50 to 65) did not alter the rate of amyloid accumulation in their study group, with one exception: people who carried the ApoE4 risk gene and had a higher education history (14 or more years of schooling).

The fact that the effects were limited to the high-education patients again points to the importance of keeping the mind and body active throughout one’s lifetime, though the authors noted it was unclear why only ApoE4 carries benefits.

A 2014 study from Amy Jak, Ph.D., a neuropsychologist at the University of California, San Diego, and colleagues might provide a hint. In their work looking at cerebral blood flow, they noticed that adults who had the ApoE4 risk gene had higher blood flow in their hippocampus (another key center for learning and memory) when sedentary. They noted that the elevated blood flow may increase the risk of stroke or other vascular damage that could contribute to dementia, and these risks might be greater in sedentary individuals whose bodies are not accustomed to activity.

Vemuri stressed, however, that “while keeping an active lifestyle might be particularly relevant for ApoE4 carriers, people without this gene should not be discouraged from exercising or doing other stimulating activities.”

He pointed out that the association between amyloid levels and Alzheimer’s is not fully understood, so higher levels may not necessarily correlate with disease onset or severity.

Becker’s study was funded through contracts that supported the Cardiovascular Health Study as well as other grants from the National Institutes of Health; Vemuri’s study was funded by grants from the National Institute on Aging; Jak’s study was funded by grants from the National Institute of Mental Health, Alzheimer’s Association, and the Sam and Rose Stein Institute for Research on Aging of the University of California, San Diego. ■

“Longitudinal Relationships Between Caloric Expenditure and Gray Matter in the Cardiovascular Health Study” can be accessed here. “Effect of Intellectual Enrichment on AD Biomarker Trajectories” is available here. “Increased Hippocampal Blood Flow in Sedentary Older Adults at Genetic Risk for Alzheimer’s Disease” is posted here.