From a pathophysiological standpoint, higher levels of physical exercise in cognitively intact older adults have been associated with reduced brain amyloid beta deposits, especially in ApoE4 carriers.11 This inverse relationship also has been demonstrated in patients who are presymptomatic who carry 1 of the 3 known autosomal dominant mutations for the familial forms of AD.12
Overall, physicians should recommend that patients—especially those with cardiovascular risk factors that increase their risk for AD—exercise regularly by following the guidelines of the American Heart Association or the American College of Sports Medicine.13 These include muscle-strengthening activities (legs, hips, back, abdomen, shoulders, and arms) at least 2 days/week, in addition to either 30 minutes/day of moderate-intensity aerobic activity such as brisk walking, 5 days/week; or 25 minutes of vigorous aerobic activity such as jogging and running, 3 days/week14 (level IA evidence for overall improvement in cognitive function; level III evidence for AD delay/risk reduction). Neuromotor exercise, such as yoga and tai chi, and flexibility exercise such as muscle stretching, especially after a hot bath, 2 to 3 days/week are also recommended (level III).15
Nineteen percent of AD cases worldwide and 7% in the United States. can be attributed to low educational attainment, which is associated with low brain cognitive reserve.5 Cognitive resilience in later life may be enhanced by building brain reserves through intellectual stimulation, which affects neuronal branching and plasticity.16 Higher levels of complex mental activities measured across the lifespan, such as education, occupation, reading, and writing, are correlated with significantly less hippocampal volume shrinkage over time.17 Frequent participation in mentally stimulating activities—such as listening to the radio; reading newspapers, magazines, or books; playing games (cards, checkers, crosswords or other puzzles); and visiting museums—was associated with an up to 64% reduction in the odds of developing AD in a cohort of cognitively intact older adults followed for 4 years.18 The correlation between mental activity and AD was found to be independent of physical activity, social activity, or baseline cognitive function.19
In a large cohort of cognitively intact older adults (mean age 70), engaging in a mentally stimulating activity (craft activities, computer use, or going to the theater/movies) once to twice a week was significantly associated with a reduced incidence of amnestic MCI.20 Another prospective 21-year study demonstrated a significant reduction in AD risk in community-dwelling cognitively intact older adults (age 75 to 85) who participated in cognitively stimulating activities, such as reading books or newspapers, writing for pleasure, doing crossword puzzles, playing board games or cards, or playing musical instruments, several times/week.21
Growing scientific evidence also suggests that lifelong multilingualism can delay AD onset by 4 to 5 years.22 Multilingualism is associated with greater cognitive reserve, gray matter volume, functional connectivity and white matter density.23
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