Medical Compass: Stay sharp as you age

Medical Compass: Stay sharp as you age

Sleep may help the brain remove waste, such as those all-too-dangerous beta-amyloid plaques linked to Alzheimer's disease. METRO photo
A few extra ZZZs can help clear brain clutter

By David Dunaief, M.D.

Dr. David Dunaief

Cognitive loss, or mental decline, is a common concern as we age. So much so that a cottage industry of app-based games has sprouted to help keep our brains sharp.

What do we know about the brain, really, though? Startlingly little. We do know that certain drugs, head injuries and lifestyle choices have negative effects, along with numerous neurological, infectious, and rheumatologic disorders and diseases.

Some, like dementia, Parkinson’s, and strokes, are recognized for some of their effects on the brain. However, others – lupus, rheumatoid arthritis, psychiatric mood disorders, diabetes and heart disease – also can have long-term effects on our brains.

These disorders generally have three signs and symptoms in common: they cause either altered mental status, physical weakness, or mood changes — or a combination of these.

Of course, addressing the underlying medical 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.

How does brain clutter affect us?

Are 20-somethings sharper and more quick-witted than those over 60?

German researchers put this stereotype to the test and 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.

What if we could reboot our brains, just like we do a computer or smartphone? This may be possible through sleep, exercise and omega-3s.

Why does sleep help?

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 an Australian study, results showed that sleep deprivation may have contributed to an almost one percent decline in gross domestic product (3). Why? When people don’t get enough sleep, they are not as productive. 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).

How does exercise help your brain?

One study with rats suggests that a lack of exercise can cause unwanted new brain connections. Rats that were not allowed to exercise were found to have rewired neurons around their medulla, the part of the brain involved in breathing and other involuntary activities. This included more sympathetic (excitatory) stimulus that could lead to increased risk of heart disease (6). 

Among the 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. We need human studies 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 or consult your personal physician.