Moderate Exercise in Middle Age Is Associated with Decreased Risk of Dementia

Of the growing body of research concerning lifestyle and brain health, and also the possibility of reduced risk of Alzheimer's and other dementias, perhaps the strongest and most consistent evidence exists for regular physical activity.

Yonas E. Geda, M.D. and colleagues at the Mayo Clinic investigated the relationship between timing of exercise (mid-life/50-65 vs. late-life/70 and above) and risk of new cases of dementia in 280 older adults (median age=81) with mild cognitive impairment (MCI) from the Mayo Clinic Study of Aging, and reported on their findings at the Alzheimer's Association International Conference® 2014 (AAIC® 2014) in Copenhagen.

A person with mild cognitive impairment (MCI) has a slight but noticeable and measurable decline in cognitive abilities, including memory and thinking skills. These changes are serious enough to be noticed by the individuals experiencing them or to other people, but they are not severe enough to interfere with daily life or independent function. People with MCI are at an increased risk of developing Alzheimer's disease.

Study participants completed a questionnaire on the frequency and intensity of exercise during their lifetime. After following the participants for about three years, the researchers found that a history of moderate physical exercise in middle age was associated with a significantly decreased risk of MCI progressing to dementia. (The association did not hold for either light or vigorous exercise in middle age, or for any level of physical activity in late life.)

In a second study reported at AAIC, the researchers looked at the timing of physical exercise and the risk of new cases of MCI. The study participants were 1,830 older adults with normal cognition from the Mayo Clinic Study of Aging. Participants underwent neurological evaluations, cognitive tests, and a self-reported questionnaire about physical exercise habits in mid-life and late-life, and were followed for an average of 3.2 years. The scientists observed that light physical exercise in mid-life and late-life were associated with decreased risk of incident MCI. Additionally, vigorous mid-life as well as moderate late-life physical exercise were associated with decreased risk of incident MCI.

"In our studies, we found that physical exercise at various levels, especially in mid-life, is beneficial for cognitive function," Geda said. "These are intriguing results, but they are not yet conclusive. More research is needed to determine the extent and nature of physical activity in protecting against MCI and dementia."