People with mild cognitive impairment (MCI) should regularly do physical exercise to help improve memory and prevent further decline, according to the American Academy of Neurology’s latest guidelines, which were endorsed by the Alzheimer’s Association.
MCI involves cognitive problems that are more severe than those that accompany normal aging, but milder than those experienced with dementia. The condition affects 10 to 20 percent of people over 65. The guidelines, published in Neurology in 2018, point to six-month studies that found that twice-weekly workouts-aerobic or strength-training-may help improve memory in people with MCI. (The guidelines also state that healthcare providers “may recommend” cognitive training for MCI, though the evidence of benefit is much weaker.) There are no effective drugs or dietary supplements to treat MCI.
What about people without cognitive impairment?
While many observational studies have suggested that exercise can help prevent cognitive decline and dementia in people who do not already have cognitive impairment, a new systematic review of clinical trials on the subject (focusing on aerobic or strength-training exercises, tai chi, or multicomponent physical activity) found that the evidence is insufficient to draw conclusions. Conducted for the Agency for Healthcare Research and Quality, the review was published in the Annals of Internal Medicine in 2018.
Regarding the positive, but not conclusive, results of some of the trials, the reviewers said, “We believe that those findings provide a signal that physical activity offers cognitive benefit but that the studies conducted were not long enough or sufficiently powered to show the true long-term effect of a physically active lifestyle…. To be effective, regular physical activity may need to begin earlier in life and be sustained as a lifestyle. Short-term interventions begun after decades of high-risk behavior likely are insufficient to reduce dementia incidence.”
Still, since physical activity may slow cognitive decline indirectly by reducing other cognitive risk factors (notably cardiovascular disease, diabetes, and obesity), the reviewers concluded that it should be encouraged for its potential, albeit still unproved, brain benefits.