Best way to fend off dementia at any age? Break a sweat, doctors say

SAN FRANCISCO – If you want strong cognition and sharp thinking skills in old age, a recent study finds that a proper exercise routine will go a long way toward keeping your brain young, no matter how old you are.

UC San Francisco scientists have discovered that the brains of physically active older adults contain more than one specific type of protein known to improve connections between neurons and help maintain healthy cognition. Importantly, autopsies show this held true even among people whose brains contained high levels of toxic proteins associated with Alzheimer’s and other neurodegenerative diseases.

“Our work is the first to use human data to show that synaptic protein regulation is related to physical activity and can drive the beneficial cognitive outcomes we see,” says the study’s lead author, Kaitlin Casaletto, PhD, assistant professor of neurology, in a college throw.

‘Vital to fend off dementia’

Although several studies have documented the benefits of exercise on brain performance among mice, consistent results among humans have been more difficult to achieve. To investigate this topic, Dr. Casaletto collaborated with William Honer, MD, a professor of psychiatry at the University of British Columbia. The research team used data provided by the Memory and Aging Project at Chicago Rush University during his study. That project tracked physical activity habits among a group of older adults, all of whom also agreed to donate their brains for analysis after death.

“Maintaining the integrity of these connections between neurons may be vital to fend off dementia, since the synapse is really the site where cognition happens,” adds Dr. Casaletto. “Physical activity— a readily available tool — can help boost this synaptic function.”

Physical activity is food for neurons

The analysis revealed that older adults who had been active had higher levels of proteins that make it possible to exchange information between neurons. This finding meshed nicely with an earlier discovery by Dr. Honer that people with more of those same proteins present in their brains at death were better able to “maintain cognition” while alive.

Furthermore, the researchers admit that it was surprising to see the beneficial effects extend beyond the hippocampus: the memory center of the mind — to additional brain regions associated with cognitive function.

“It may be that physical activity exerts a global sustaining effect, supporting and stimulating the healthy function of proteins that facilitate synaptic transmission throughout the brain,” explains Dr. Honer.

As most brains age throughout life, they accumulate amyloid Y Tau proteins. Studies show that those two substances appear to be the hallmarks of Alzheimer’s disease progression. Today, many scientists believe that amyloid accumulates first, followed by the accumulation of tau, ultimately resulting in the disintegration of synapses and neurons.

Dr. Casaletto had previously found that synaptic integrity, regardless of whether scientists measure it in living adult cerebrospinal fluid or within brain tissue during an autopsy, appears to “dampen” the relationship between amyloid and tau, and between tau Y neurodegeneration.

“In older adults with higher levels of proteins associated with synaptic integrity, this cascade of neurotoxicity that leads to Alzheimer’s disease appears to be attenuated,” concludes the researcher. “Taken together, these two studies show the potential importance of maintaining synaptic health in supporting the brain against Alzheimer’s disease.”

the to study is published in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association.