Fitness: Exercise can help ward off cognitive decline as we age

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Much of the focus on exercise is how it benefits physical health, including stronger muscles, improved endurance, more energy, better balance and enhanced mobility. But what’s often ignored is the effect physical activity has on cognitive health.

We know kids perform better in school after a bout of exercise. Attention, memory and time on tasks all improve when children have a chance to move around. But kids aren’t the only ones to benefit from the brain-healthy effects of physical activity. Dementia, including Alzheimer’s disease, robs older adults of their independence and quality of life. With the number of people over 65 years of age increasing, the World Health Organization estimates nearly 82 million people worldwide will be living with dementia by 2030.

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As prevalent as dementia will become, even more of our aging population will be struggling with mild memory loss. While not as severe as Alzheimer’s, chronic forgetfulness affects daily life. With no cure in sight, prevention is the best way to delay or abate memory loss. And like other chronic diseases associated with aging, exercise is an important factor in warding off cognitive decline.

Regular physical activity improves cognitive health in a variety of ways. The added blood flow that accompanies most moderate- to vigorous-intensity exercise improves brain function. And when performed on a regular basis, it also affects brain volume. Studies have shown a two-per-cent increase in brain volume among older adults (65+) who exercised regularly for a year compared with a 1.4-per-cent decline in a group of same-aged women enrolled in a stretching program.

In addition to increased brain volume, exercise boosts the production of specific molecular and biochemical mechanisms that support the ongoing health of the brain. It also reduces the type of inflammation that can speed up cognitive decline. But as much as is known about how exercise changes brain structure, debate remains about how much these changes actually slow down the onset of dementia or reduce the risk of mild memory loss.

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To get a better overview of just how effective exercise is in preserving cognitive function, a team of researchers from Stanford University in California reviewed 17 high-quality studies investigating exercise and brain health. Most reported improvements in long- and short-term memory among study subjects who followed a regular exercise routine. More complex cognitive skills, including organization, attention to tasks, planning, multi-tasking and working memory also improved.

“Studies consistently report that regular physical exercise results in modest improvement in global cognitive function during activity participation among people without dementia,” the researchers say.

Yet despite what the researchers describe as “modest” results, it’s worth noting that exercise produced improvements on the same scale as many of the more commonly prescribed medications designed to slow cognitive decline.

Interestingly, women involved in a six-month prescribed exercise routine seemed to respond better to selective memory tests than men. But for men and women alike, the risk of dementia is the lowest among older adults with high levels of aerobic fitness. In fact, most of the studies featured aerobic exercise: walking, running and cycling versus resistance training. That doesn’t mean working out in the weight room isn’t an effective deterrent to memory loss. There’s evidence to suggest the best exercise routine to stimulate the brain is one that employs a variety of activities versus repeating the same workout several times a week.

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Yet as effective as exercise is, you need to keep moving if you want to maintain the cognitive benefits you gained. Most followup testing among study subjects found that the effects of exercise started abating when they left the study and were no longer active.

“Studies in this review found decay in global cognitive improvements within six months after participants stopped participating in physical activity interventions, suggesting that permanent changes in cognition and brain health are unlikely in this age group following moderate duration interventions,” the researchers said.

As for whether you need to sweat your way through a tough workout to reap the memory-boosting effects of exercise, again the jury is still out. But so far the evidence seems to suggest cognitive health improves regardless of whether you choose to walk or run.

Finally, there’s a caveat to all the good news surrounding the positive effects exercise has on memory. So far the results seem to be strongest among those with little or no memory loss.

“These findings suggest that sustained physical exercise can have a clinically meaningful impact on cognition and brain health among older adults prior to onset of dementia that decays when people stop exercising,” the researchers said.

That means if you are middle-aged or beyond, now is the time to settle into a regular exercise routine. It doesn’t need to be a heart-pumping, sweat-inducing workout. A daily stroll with generous bursts of brisk walking should do the trick. The goal is to find a routine that is sustainable versus impressive in its intensity. Don’t wait for memory to fail before reaping whatever benefits you can from regular exercise. In the case of cognitive health, an ounce of prevention is worth a pound of cure.

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