For a while now, it’s believed that exercise and brain health go hand in hand, and a few studies in the last year have begun to prove a link between physical activity and cognition does exist. This connection is important not only because exercise and aging can enhance our minds, but because it may ward off dementia and memory loss. In essence, researchers are getting closer to uncovering just how exercise and brain health are connected.
(Project Bold Life has examined the link between exercise and healthy aging before–read up on it here!)
While physical activity and cognition do appear to affect one another, it remains unclear exactly how this happens. But there may be more than one mechanism. First, there is now evidence to suggest that exercise reduces inflammation in the brain. This could naturally ward off dementia and improve brain function. Second, physical activity also seems to boost connections between nerve cells. This too would enhance our ability to think. In all likelihood, there are probably other mechanisms as well. But from a practical perspective, it’s important that we realize that exercise and brain health are indeed connected.
“Our work is the first that uses human data to show that synaptic protein regulation is related to physical activity and may drive the beneficial cognitive outcomes we see.” – Kaitlin Casaletto, PhD, Assistant Professor of Neurology, UC San Francisco
Good Proteins Over Bad Ones
When it comes to conditions like Alzheimer’s dementia, there are some well-known hallmarks of the disease. Specifically, in individuals with this illness, two specific proteins are usually found in their brains that cause problems. One is amyloid protein and the other is tau protein. As we age, these proteins accumulate in brain cells and eventually lead to cell death. And the more neurons affected, the higher the risk of developing dementia. Interestingly, however, scientists at UC San Francisco have found that exercise increase “good” proteins that counterbalance these bad ones. In fact, in older adults who remain active, they have proteins that strengthen the connections between neurons called synapses. Even though brain autopsies bad proteins exist, individuals with these good proteins did not necessarily show signs of dementia.
The study used data from the Memory and Aging Project at Rush University in Chicago. In the research, scientists followed over 400 older adults between 86 and 90 years of age using activity trackers. They assessed their physical activity and cognition over time, and they then examined their brains after death. They found that those who were most active did the best. While only a third had dementia clinically, roughly 60% had dementia-related proteins. And the ones of this group who exercised the most were the ones who had normal cognitive function. The scientists’ conclusions were that exercise and brain health were clearly linked as a result of their findings.
“It may be that physical activity exerts a global sustaining effect, supporting and stimulating healthy function of proteins that facilitate synaptic transmission throughout the brain.” – William Honer, MD, Professor of Psychiatry, University of British Columbia
The Muscle-Brain Crosslink
It would appear that a higher level of good proteins in the brain explains why exercise and brain health are linked. But as it turns out, this isn’t the only connection. Our muscles play a role in the connection between physical activity and cognition as well. In another study, scientists used the same database of patients out of Rush University. But in this instance, they followed only 167 patients during their final years of life. In addition to tracking their levels of exercise, they also investigated the amount of inflammation in the brain at autopsy. As it turns out, those who were most active had the least amount of brain tissue inflammation. Researchers attributed this to the production of hormones that muscles produce during activity called myokines. The more myokines present, the less inflammation in the brain was seen.
Myokines are basically muscle hormones that are produced when muscles contract and exercise. As part of the endocrine-hormone system, these molecules communicate to other organs, and the brain is one of those. In this study, the myokines produced reduced the level of activation of special brain cells called microglia. Microglia are the inflammatory cells of the brain, which often help us fight off infection, cancers and toxins. But they can also become chronically activated and cause conditions like dementia when we age. As it turns out, myokines help prevent this unwanted chronic activation of microglia. Thus, this is another way that exercise and brain health may be connected.
“The environment and our lifestyle choices can have a big effect on the way we age. So if I had to say one thing, it would be, Keep yourself active—even if it’s walking a few minutes a day. If you can, then do that.”- Karina Alviña, an assistant professor of neuroscience at the University of Florida College of Medicine
Solving the Exercise-Dementia Equation
There’s little question that physical activity and cognition are connected. Many studies have suggested that exercise can enhance creativity as well as mood and emotions. Now, several studies are showing how exercise and brain health result through different mechanisms. One touts anti-inflammatory, hormonal effects while the other links physical activity and cognition via brain proteins. Without question, there are likely to be other ways exercise and brain health are associated waiting to be discovered. In any case, there is one important takeaway that is obvious. Being physically active is one of the best ways to help preserve memory, learning and complex thought. And it may very well be the best way to stave off dementia as well.
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