It appears that regular aerobic activity — everyday exercise — may actually fend off the onset of Alzheimer’s pathology in the brain, according to new research from Washington University in St. Louis.
In the study, which included 69 participants ages 55 to 88, scientists analyzed the association between exercise habits and the presence of Alzheimer’s disease’s biological markers, or biomarkers.
These biomarkers show the amounts of certain proteins in the brain and spinal fluid that are typically found during the progression of Alzheimer’s. Altered levels of these proteins may indicate the presence of the disease before symptoms appear.
“This novel association, in conjunction with the animal work, suggests that it may be useful for physicians to recommend exercise engagement not only for Alzheimer’s symptoms but also potentially for preventative care,” says Denise Head, PhD, assistant professor of psychology.
“We have not researched to the point where it can be proven that exercise helps prevent Alzheimer’s symptoms, but that’s the direction we’d like to go.”
The study participants, all of whom had normal cognition, answered questions regarding their exercise habits during the previous 10 years. Researchers then analyzed the participants’ cerebrospinal fluid samples and PET scan images of a brain protein called amyloid that builds up as ‘plaque’ in the brains of Alzheimer’s patients.
The scientists used the American Heart Association’s (AHA) recommendation of 30 minutes of moderate exercise five days a week as a baseline for measuring activity levels.
The findings reveal that participants who exercised at levels close to or greater than those recommended by the AHA over the past decade had lower levels of amyloid in the brain as well as clues of decreased levels of another protein called tau, a sign of dysfunction and/or death of neurons.
Results of this study provide critical, useful knowledge toward slowing a potential public health crisis. As of now, 4.5 million Americans have Alzheimer’s disease, and that number is expected to reach 13.2 million by 2050.
“With the growing aging population in the U.S., Alzheimer’s is going to become an increasingly prevalent disease affecting many families and taking a significant financial toll,” says Kelvin Y. Liang, Head’s MD/PhD student and lead author of the study.
“Because the disease has a such a long timeline, we’re looking at a lot of lifestyle and other factors, such as exercise, that could prevent the disease before it gets to the stage where you have clinical symptoms — where there may not be as much you can do about it,” Liang says.
The research team doesn’t know the exact mechanism by which physical activity may affect Alzheimer’s biomarkers, but exercise is known to have positive effects on the memory-related hippocampus that is implicated in Alzheimer’s.
Exercise also has been linked to the strength of several vital components, including blood vessels and chemicals that support the health of neurons in the brain.
“Our study was a first step,” Head says. “Now there are two possible interpretations we need to tease apart: does exercise lead to lower amyloid deposition or does amyloid deposition lead to less exercise? Future studies also need to look at the influence of other relevant lifestyle factors that may interact with exercise engagement.”
As they plan future studies in this area, the researchers keep in mind that their science exists to serve people suffering from Alzheimer’s.
“A researcher can be really focused on a particular part of a certain mechanism of this disease that he or she is studying, and that’s an important step in developing therapies and other diagnostic tests,” Liang says. “But in the end, we should always keep in mind that everything we do is to benefit the patient.”