Why exercise protects and enhances brain health

club running

As runners, it is good to know that you are enhancing your grey matter by regularly exercising. Both physical and mental activity preserve cognitive skills, potentially lowering dementia risk.

Many of us get 150 minutes+ of moderate-intensity aerobic physical activity a week to improve physical fitness.  What you might not realize is that with every step every mile or every lap you take, you’re enhancing your cognitive fitness. Recent studies suggest that the activities you do to improve your body also benefit your brain.

“We know that physical exercise, and aerobic exercise in particular, is very beneficial for maintaining brain health, even in people who are at risk for developing dementia and Alzheimer’s disease (AD),” says neuropsychologist Aaron Bonner-Jackson, PhD. “You can make a major difference in terms of how your body is functioning and, as a result, how your brain is functioning.”

So, to preserve your cognitive health, your best bet is to work out your body and your mind through regular exercise and mentally and socially stimulating activities.

Get moving for your brain

One study published in 2013 looked at healthy behaviors in nearly 2,300 men over the course of thirty years. Researchers looked at the participants' behaviours and cognitive abilities starting in middle age tracked their progress throughout old age.

The researchers found that men who practiced certain healthy behaviorus were around 60% less likely to experience cognitive impairment and dementia as they age.

The adults underwent yearly physical exams and cognitive tests for 20 years and agreed to donate their brains for research when they died. The participants were given accelerometers, which tracked their movement and physical activity around the clock.

Those who moved more scored better on the memory and thinking tests, and every increase in physical activity by one standard deviation was associated with a 31% lower risk of dementia, the researchers reported. The association between physical activity and cognitive function remained consistent even after the study authors accounted for the participants’ brain pathology and whether or not they had dementia, according to the study.

In another recent study, 160 sedentary older people with mild cognitive impairment were assigned to take part in several options. They could do aerobic exercise (3x45 minutes per session/weekly), eat a heart-healthy Dietary Approaches to Stop Hypertension (DASH) diet, combine aerobic exercise with the DASH diet, or receive health education.

During the six-month study, those who followed the DASH diet alone did not improve on assessments of executive function (responsible for tasks like planning, problem-solving and multitasking), while the health-education group’s function worsened, according to the study. However, those who exercised showed improvements in thinking and memory, and those who combined exercise and the DASH diet improved even more, the researchers reported.


How does exercise help your brain?

Physical activity may benefit the brain in a number of ways, such as:

    Promoting cardiovascular health.

    Improving blood flow to the brain.

    Reducing inflammation.

    Lowering levels of stress hormones.

All of these factors can adversely affect cognition, Dr. Bonner-Jackson explains.

Exercise may provide physical benefits to the brain, too, such as increasing the thickness of the cerebral cortex and improving the integrity of your white matter, the nerve fibres that connect areas of the brain’s nerve-cell-rich gray matter. It also promotes neuroplasticity, your brain’s ability to form new neural connections and adapt throughout life. “One of the key places that happens is in the hippocampus, which is a very important area of the brain for memory,” Dr. Bonner-Jackson explains.

    What’s especially encouraging is you don’t necessarily have to go overboard or meet the physical activity guidelines in order to benefit your brain.

In one recent study, researchers concluded that even among people who did not meet the activity guidelines, each hour of light-intensity physical activity and achieving 7,500 steps or more daily was associated with higher total brain volume. This was “equivalent to approximately 1.4 to 2.2 years less brain aging.”

“There are a lot of potential mechanisms of exercise that may be combining to benefit brain health,” Dr. Bonner-Jackson says. “In general, even in people who are at risk for development of Alzheimer’s or other dementias, it can stave off decline in some cases for many years and help people function better.”

What you can do

    Stay physically active. Aim for 150 minutes of moderate-intensity aerobic activity (like walking, jogging, biking etc.) a week, and realise that any physical activity can benefit your brain. Try one of our beginners training plans below.

Part of his article originally appeared in Cleveland Clinic Men’s Health Advisor.

And the VeryWellMind Psychiatry site here