Making Exercise a Habit Prevents Age-Related "Brain Drain"

Aerobic exercise is neuroprotective and keeps your brain cells healthy.

Posted Oct 29, 2015

Dave Bredeson/Dreamstime
Source: Dave Bredeson/Dreamstime

There is growing evidence that the structural deterioration of the brain associated with older age can be prevented if a long-term habit of aerobic exercise begins in mid-life. Recent findings suggest that it's never too late, or too early, to kickstart your commitment to make physical activity a part of your daily routine. That said, midlife appears to be a particularly important stage of life to make some type of physical activity a habit. 

Age-related cognitive decline is caused partly by changes in neural function, but cognitive deficits are also correlated with deficiencies in the blood supply to the brain and with low-level inflammation. For many people, the aging process brings along with it the risk of neurodegenerative maladies such as Alzheimer's disease (AD) and dementia.

In recent years, a wide range of studies have shown that physical activity ameliorates cognitive decline and sensorimotor deficits typically seen in older humans, and in older mice. However, the specific neurobiological process that leads to the age-related decline of brain structure and function has remained enigmatic until recently.

Exercise Can Help Keep Your Brain Healthy and Young for a Lifespan

Yesterday, Gretchen Reynolds published an article, "Does Exercise Slow the Aging Process?" in the New York Times. Her article reports on a new study which found that even small amounts of physical activity may slow the aging process deep within our cells by protecting the length of someone's telomeres.

Stanford University School of Medicine
Telomeres in green. 
Source: Stanford University School of Medicine

Telomeres are the protective caps on the ends of chromosomes that affect how quickly cells age. They are combinations of DNA and protein that help cells remain stable by protecting the ends of chromosomes. As telomeres become shorter, their structural integrity weakens, which causes cells to age and die younger.

The October 2015 study, "Movement-Based Behaviors and Leukocyte Telomere Length among US Adults," conducted by researchers from University of Mississipi and the University of California, San Francisco, found that middle age is an especially critical time period to make exercise part of your daily routine. Paul Loprinzi, an assistant professor of health and exercise science at the University of Mississippi et al found that people between the ages of 40 to 65 who performed any type of exercise were less likely to show the shortening or fraying of their telomeres. 

A growing body of research from around the world strongly supports Loprinizi's closing quotation in Reynolds' NYT article, "So the message seems clear. “Exercise is good” for your cells, and “more exercise in greater variety” is likely to be even better."

A few days ago, I wrote a Psychology Today blog post, "Physical Activity Is the No. 1 Way to Keep Your Brain Young," which was inspired by an October 2015 study conducted by researchers in Japan who found that aerobic fitness in older men ages 64-75 was associated with improved cognitive function and maintaining the brain health of younger adults.

Today, another October 2015 study reported on the importance of doing regular aerobic exercise to maintain a younger brain beginning in mid-life. The study, “APOE Stabilization by Exercise Prevents Aging Neurovascular Dysfunction and Complement Induction,” was published in the open access journal PLOS Biology.

In this paper, researchers from the Jackson Laboratory (JAX) in Maine found that long-term aerobic exercise from mid-life to old age prevented age-related neurovascular decline in mice who were allowed to run regularly. The JAX scientists investigated the changes in the brains of younger and older laboratory mice by comparing their gene expression profiles using a technique called RNA sequencing. Then, they compared their brain structures at high-resolution using fluorescence microscopy and electron microscopy. 

In a press release, Ileana Soto, Ph.D., lead author of the study said, "Collectively, our data suggests that normal aging causes significant dysfunction to the cortical neurovascular unit, including basement membrane reduction and pericyte loss. These changes correlate strongly with an increase in microglia/monocytes in the aged cortex."

Soto and her colleagues from Gareth Howell's Lab at JAX found that the structural changes that make the blood-brain barrier leaky—and result in inflammation of brain tissues in old mice—can be mitigated by allowing mice to run regularly. Running appeared to prevent "brain drain." These findings also provide a potential explanation for the benefits of aerobic exercise on dementia in humans. 

Allofus/Labeled for reuse
Source: Allofus/Labeled for reuse

The young and old mice all ran about two miles per night. This physical activity improved the ability and motivation of the old mice to engage in the typical spontaneous behaviors that seem to be affected by aging. Running significantly reduced age-related pericyte loss in the brain cortex and improved other indicators of dysfunction of the vascular system and blood-brain barrier. 

Previous studies have found that exercise is beneficial for the human brain and that the effects of exercise on mice are relevant to human health. The authors conclude, "Our data, supported by data from human studies, point towards focusing efforts on understanding the impact of aging and lifestyle choices on neurovascular unit decline and neuroinflammation, particularly astrocyte and pericyte dysfunction."

Conclusion: Mens Sana in Corpore Sano (A Healthy Mind in a Healthy Body)

The Ancient Greeks and Romans understood the inherent link between physical fitness and mental fitness. In many ways, the foundation of their societies was built upon the principles of Mens Sana in Corpore Sano which is Latin for "A sound mind in a sound body" or "A healthy mind in a healthy body."

In the press release for his recent study, Grant Howell from JAX drives home the point that we need to work hard as a society and individuals to ensure that anyone who is able to exercise makes daily physicality a habit. Howell concludes, "In this day and age, with so many distractions and conveniences, it is easy to fall into a lifestyle that does not include enough exercise. With an aging population, I hope our study helps in encouraging a healthy lifestyle that includes exercise." I couldn't agree more.

As a modern society living in a sedentary digital age, we all need to make an extra effort to stay physically active. If we are chronically inactive, research shows that our bodies and minds will deterioate more quickly at a cellular level. Each of us can either find ways to motivate and enable ourselves to maintain a "sound mind in a sound body" now... or, we can pay exponentially for it later in the form of skyrocketing health care costs and the brain drain of physical inactivity.  

If you'd like to read more on this topic, check out my Psychology Today blog posts,

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