Medical Compass: Improving brain health

Medical Compass: Improving brain health

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Lack of exercise may rewire the brain

By David Dunaief, M.D.

Dr. David Dunaief

What do we know about the brain? Startlingly little.

Certain drugs, head injuries and lifestyle choices have negative effects. Also, numerous disorders and diseases affect the brain. Among these are neurological, infectious and rheumatologic disorders. These can include dementia, Parkinson’s, strokes, meningitis, lupus and rheumatoid arthritis. Cancer, psychiatric mood disorders, diabetes and heart disease also have potential long-term effects.

Although this list is long, it’s not exhaustive. And while these diseases vary widely, they generally have three signs and symptoms in common: they cause either altered mental status, physical weakness or change in mood — or a combination of these.

Cognitive loss, or mental decline, is a common fear and potential side effect of many of these disorders and diseases. Of course, addressing the underlying disorder is critical. Fortunately, several studies also suggest that we may be able to help our brains function more efficiently and effectively with rather simple lifestyle changes: sleep, exercise and possibly omega-3s. Let’s look at the evidence.

Clearing brain clutter

How many of us believe the stereotype that those in their 20s are sharper and quicker-witted than older folks? Are they really?

In a study, German researchers found that educated older people tend to have a larger mental database of words and phrases to pull from since they have been around longer and have more experience (1). When this is factored into the equation, the difference in terms of age-related cognitive decline becomes negligible.

This study involved data mining and creating simulations. It showed that mental slowing may be at least partially related to the amount of clutter or data that we accumulate over the years. The more you know, the harder it becomes to come up with a simple answer to something. We may need a reboot just like a computer. This may be possible through sleep, exercise and omega-3s.

Sleep removes brain waste

Why should we dedicate a large chunk of our lives to sleep? Researchers have identified a couple of specific values we receive from sleep: one involves clearing the mind, and another involves productivity.

For the former, a study done in mice shows that sleep may help the brain remove waste, such as those all-too-dangerous beta-amyloid plaques (2). When we have excessive plaque buildup in the brain, it may be a sign of Alzheimer’s. When mice were sleeping, the interstitial space (the space between brain gyri, or structures) increased by as much as 60 percent.

This allowed the lymphatic system, with its cerebrospinal fluid, to clear out plaques, toxins and other waste that had developed during waking hours. With the enlargement of the interstitial space during sleep, waste removal was quicker and more thorough, because cerebrospinal fluid could reach much farther into the spaces. A similar effect was seen when the mice were anesthetized.

In another study, done in Australia, results showed that sleep deprivation may have been responsible for an almost one percent decline in gross domestic product for the country (3). The reason? People are not as productive at work when they don’t get enough sleep. They tend to be more irritable, and their concentration may be affected. While we may be able to turn on and off sleepiness on short-term basis, we can’t do this continually.

According to the Centers for Disease Control and Prevention, 4.2 percent of respondents reported having fallen asleep in the prior 30 days behind the wheel of a car during a 2009-2010 study (4). Most commonly, these respondents also reported getting usual sleep of six hours or fewer, snoring, or unintentionally falling asleep during the day. “Drowsy driving” led to 91,000 car crashes in 2017, according to estimates from the National Highway Traffic Safety Administration (5).

Make time for exercise

How can I exercise when I can’t even get enough sleep? Well, this study may inspire you.

In the study, rats that were not allowed to exercise were found to have rewired neurons in the area of their medulla, the part of the brain involved in breathing and other involuntary activities. There was more sympathetic (excitatory) stimulus that could lead to increased risk of heart disease (6). In rats allowed to exercise regularly, there was no unusual wiring, and sympathetic stimuli remained constant. This may imply that being sedentary has negative effects on both the brain and the heart.

This study suggests that a lack of exercise causes unwanted new connections. Human studies should be done to confirm this impact.

Omega-3 fatty acids may affect brain volume

In the Women’s Health Initiative Memory Study of Magnetic Resonance Imaging Study, results showed that those postmenopausal women who were in the highest quartile of omega-3 fatty acids had significantly greater brain volume and hippocampal volume than those in the lowest quartile (7). The hippocampus is involved in memory and cognitive function.

Specifically, the researchers looked at the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in red blood cell membranes. The source of the omega-3 fatty acids could have been either from fish or from supplementation.

It’s never too late to improve brain function. Although we have a lot to learn about the functioning of the brain, we know that there are relatively simple ways we can positively influence it.


(1) Top Cogn Sci. 2014 Jan.;6:5-42. (2) Science. 2013 Oct. 18;342:373-377. (3) Sleep. 2006 Mar.;29:299-305. (4) (5) (6) J Comp Neurol. 2014 Feb. 15;522:499-513. (7) Neurology. 2014;82:435-442.

Dr. David Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit