Can regular exercise slow dementia?

Chances are good that almost everyone reading this has had someone in their life affected by age-related cognitive decline, commonly called dementia.

According to the Alzheimer’s Association, one in three adults over the age of 65 will die from Alzheimer’s disease (AD) or another type of dementia.

Before we get into the details, we need to define some terms that are often used when discussing cognitive decline. Dementia can be seen as an umbrella grouping several different conditions that cause cognitive problems. Alzheimer’s disease (AD) is a specific pathological process that eventually leads to dementia.

Dementia is characterized by memory loss, difficulty planning and organizing tasks, problems performing familiar tasks at home or at work, frequent loss of objects, and new difficulties with speaking or writing. It can start as early as age 40-50 and becomes more common after age 65.

Over the past few years, research has shown that one of the factors that contribute to whether someone will develop dementia is how well the total volume of gray matter in the brain is preserved in the aging process. Improved blood flow appears to be one mechanism that contributes to gray matter preservation.

According to the American Physiological Society, “higher cardiorespiratory fitness is associated with lower rates of age-related gray matter decline.” It appears that people with better cardiovascular fitness tend to lose less gray matter as they age.

The amount of walking people do daily is also related to gray matter preservation. People who walk at least ½ mile each day are at lower risk of developing dementia of all types.

To learn more about how exercise can protect against dementia, I spoke with local physician Dr. Wendy Walker, MD. Walker is Board Certified in Family Medicine and a partner at MDVIP in Petoskey.

More generally, what are the proposed mechanisms for how exercise improves cognitive outcomes?

To maintain normal cognitive function, the brain needs a constant supply of oxygen and other chemicals delivered through its abundant blood vessels. Exercise helps the efficient circulation of nutrient-rich blood in the body and keeps the blood vessels healthy. Exercise increases the creation of mitochondria—the cellular structures that generate and sustain our energy—in both our muscles and our brains, which may explain the mental edge we often experience after exercise. Studies also show that increasing heart rate improves neurogenesis—the ability to grow new brain cells—in adults.

Is there a “best” type of exercise that people should engage in?

There are no “best” types of exercise. For inactive adults, even replacing one hour of sitting with a variety of non-exercise activities (eg, housework, lawn and garden work, and a daily non-exercise walk) was associated with reduced all-cause mortality.

Can exercise help prevent age-related cognitive changes?

Exercise is associated with improved cognitive function in both young and older adults. In fact, if you exercised as a teenager, the benefits carry over into late adulthood. However, it is unclear whether physical activity prevents dementia and cognitive decline.

How much exercise do you recommend for your patients who are either experiencing or at risk of cognitive decline?

Any amount of exercise is considered good, and studies show that it depends on the dose. The more you do, the better you get! A general rule of thumb is brisk walking or something similar for 30 minutes every day.

Jeff Samin is a physical therapist, board certified orthopedic clinical specialist and board certified strength and conditioning specialist at the Northern Michigan Sports Medicine Center in Petoskey. He can be reached by email at [email protected]. This information should not be considered medical advice and is not intended to replace consultation with a qualified medical professional.

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