Did you forget where you put your keys? They’re in the refrigerator where the milk should be that you forgot to buy when you went shopping. Does this sound like you, or do you fear that it could be you in a few years? Is it a sign of normal cognitive decline as we get older, or is it the start of something more serious, such as Alzheimer’s or another form of dementia? What if we could lower the risk of such a fate by up to 50% through regular exercise?

Not surprisingly, physical exercise increases physical health and mental exercises have been shown to increase mental functioning. But, somewhat surprisingly, research shows that physical exercise can slow or reverse cognitive decline as we age. You may have heard the phrase “mind over matter,” but the mind-body connection is not a one-way street—what goes on in our body influences what goes on in our brain.

The US population of those aged 65 years or older is expected to more than double, from 43 million to 92 million, by the year 2060. The prevalence of dementia and other cognitive impairment is also expected to increase incrementally. Normal aging is accompanied by alterations in brain structure and function, and associated cognitive changes. Although declines in cognition attributed to the normal aging process are well documented, some of these changes may be related to neurodegenerative diseases such as Alzheimer’s disease and other types of dementia. In those over 71 years of age, the prevalence of dementia in the US is estimated to be nearly 14%. The estimated prevalence of cognitive impairment not categorized as dementia, including mild cognitive impairment, is 22%. Studies report reduced risk for mild cognitive impairment and dementia in older adults who maintain higher levels of physical activity. As physical exercise is essential in maintaining physical function and physiological health, it also appears to be critical in maintaining brain health and cognitive performance in older adults.

Normal age-related changes in executive function include: decline in tasks that involve attention-switching (multitasking), difficulty in instrumental activities of daily living, slower response times, reduced speed of information processing, and reduced inhibitory control. Brain atrophy in key regions appears to occur prior to detectable cognitive changes. Brain regions vulnerable to age-related and disease-related atrophy, however, have also demonstrated changes in structure and function in response to moderate aerobic exercise—suggesting that physical exercise may enhance brain health and spur improvements in cognitive performance.

Physical exercise that contributes to the reduction of cardiovascular risk factors is positively associated with indicators of brain health and improved cognitive performance. By affecting abnormal protein deposits, increasing growth of brain tissue, improving cerebral blood flow, and decreasing systemic inflammation, physical exercise may protect against degenerative brain changes associated with aging and neurodegenerative disease. A combination of exercise-mediated physiologic changes contributes to improved cognitive performance in animal studies. Research in older adults has demonstrated relationships between brain structure and function, cardiorespiratory fitness, and cognitive performance in relation to exercise levels. 

One study suggests that cardiorespiratory fitness may offer a protective effect on the brain by modifying Alzheimer’s-related changes in brain structure. Evidence from studies that measure brain connectivity using functional MRI suggests that the brains of older adults with higher levels of fitness are working more effectively than those who have lower levels of fitness. People who are more active in midlife and late life have lower risk for global cognitive decline, and dementia. Importantly, the exercise volume which appeared to be protective is similar to the amount of exercise recommended for all older adults. Studies suggest a protective effect of high levels of physical activity that reduces the risk of Alzheimer’s by 45%. Another study found that those engaging in more than four different physical activities had only half the risk of dementia when compared to people engaging in one or no physical activities. Any frequency of moderate exercise in midlife or late life was associated with reduced odds of cognitive impairment. Exercise durations of 6–12 months are often needed before cognitive changes are detected.

Physical exercise provides a non-pharmacological approach to slowing age-related decline and reducing disease-related cognitive impairment in older adults. Higher levels of physical exercise are associated with reduced risk for cognitive impairment and dementia. Studies provide compelling evidence that exercise can modify the metabolic, structural, and functional dimensions of the brain that preserve cognitive performance in older adults. 

The risk of dementia is my number-one worry about growing older. I have seen its effects in my family, and I do not want to go through that process of mental decline. I am encouraged that research suggests that we may be able to cut our risk in half through regular exercise. I am already engaged in daily activity—primarily for physical health benefits and weight loss. I am happy to learn that my existing regimen could prevent cognitive decline and dementia, as well. If you needed one more reason to get off the couch, hopefully, this is it.