"What Are You Doing?" with Jo Zimmerman

From better sleep to more energy to a longer and healthier life, the benefits of exercise are numerous. But can physical activity reduce or delay a decline in cognitive function as we get older? Can it slow or stop the onset of Alzheimer’s Disease?

In our first “What are you doing?” feature, the Healthy Turtle talked with Jo Zimmerman, a doctoral candidate in the Kinesiology department, about research she’s worked on regarding this exciting prospect.

The study focused on a particular gene called ApoE, a gene that has been linked with decreased efficiency in the brain as we age.. People with this gene are more at risk for cognitive decline, and about 20% of people who have this gene have the e4 variety, a strong risk factor for late onset Alzheimer’s disease.

Zimmerman breaks down brain efficiency like this: imagine that a 12-lane highway is slowly reduced to a one lane country road. You would need more time and more resources to do the same things as the road diminished in size, and this is exactly what’s happening in your brain as it loses efficiency.

From remembering where your keys are to doing the crossword puzzle, lower efficiency means that you would have to use more of your brain to do the same things. And while people may not see it or feel a difference, researchers like Zimmerman can measure decreases in the lab.

The Study:

To measure the effects of exercise on the cognitive decline associated with the ApoE gene, Zimmerman and her colleagues recruited people between the ages of 50 and 70 who were “apparently healthy” and separated them into 4 groups based on whether or not they carried the ApoE gene (Carriers vs. Noncarriers) and whether or not they were active (Active vs. Nonactive).

To measure their brain function, Zimmerman and others scanned their brain with a “huge brain scanning machine” (there is probably a more technical function and name for this machine, but I’m not bright enough to explain it) and had participants work through a computer program that tests function. These tests were done to measure brain reaction time, examining function on a fundamental level.

Zimmerman noted a few things about their methodology: the study did not include any intervention, only measuring already active people with already nonactive people. They also used a reasonable representation of the surrounding region, which includes many people with higher levels of education, a trait that studies show protects your brain from decline.

The Results:

What they found was that there was no statistically significant difference between active noncarriers, active carriers, and nonactive noncarriers. But, nonactive carriers performed worse in several key areas.

To put another way, carriers of ApoE who were active had appreciably higher levels of cognitive function than carriers who were nonactive.

These are promising results, but Dr. Zimmerman cautioned that the ApoE gene is not an on/off switch. While this gene does accelerate aging in some areas of the brain, and while it does appear that exercise puts the brakes on, there are countless other factors at play in your brain. You don’t need to go get tested for this gene, she said, adding that worrying about it will cause more damage over your lifetime than the gene itself.

Moving forward, researchers are looking at how much physical movement matters to cognitive function as you age, and Zimmerman noted a few studies that were looking at the same question. In particular study, Canadian scientists looked at dancing in elderly people, an activity that offers not only physical movement but social engagement, memory, learning, and many other benefits.

So what did we learn? The questions that we asked at the top are still unclear, but we do know that physical movement and exercise is vastly beneficial to people, and may help slow cognitive decline in some. While there may be a link between ApoE and alzheimer’s disease and decreased brain efficiency, countless other things must be factored in to give a comprehensive understanding of how our brains age.

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Thanks to Jo Zimmerman for her time in putting this feature together.