Older adults with memory impairment who exercised regularly for 1 year may have had less cognitive decline compared with those who received no intervention, according to a large, multisite study comparing different types of physical activity to usual care.
Researchers enrolled 296 sedentary adults aged 65 to 89 years with amnestic mild cognitive impairment (aMCI), a condition that often precedes Alzheimer’s disease. Participants were randomly assigned to two exercise groups: moderate-to-high intensity aerobic training or low-intensity stretching, balance, and range-of-motion activities. Each group exercised four times per week at community YMCAs under trainer supervision for 12 months.
The researchers compared outcomes from the two exercise groups with a matched sample of older adults with similar characteristics from a separate observational study who didn't receive any intervention. All groups were similar in age, education, race, baseline cognitive test scores, and APOE ε4 status.
After 12 months, both exercise groups showed significantly less decline on the Alzheimer’s Disease Assessment Scale–Cognitive-Executive (ADAS-Cog-Exec), a composite test evaluating memory, attention, language, and executive function. The aerobic group had a beta coefficient of 0.169 (95% confidence interval [CI] = 0.011–0.328), and the stretching group had a beta of 0.181 (95% CI = 0.007–0.354), each compared with their matched controls.
Brain imaging results showed no statistically significant differences in overall brain volume between exercise and control groups. However, the aerobic group showed less shrinkage in the entorhinal cortex, a memory-related region that often atrophies early in Alzheimer’s disease. The entorhinal cortex difference was statistically significant (beta = 73.64, 95% CI = 27.55–119.72, P = .002).
While structural brain changes were mixed, the researchers noted the entorhinal finding could help explain the cognitive benefit observed in the aerobic group.
The study wasn't designed to compare which type of exercise was superior, but rather whether structured physical activity—regardless of intensity—offered cognitive protection. Both interventions were found to be beneficial compared with no exercise.
“Sedentary older adults with aMCI in the aerobic exercise and stretching/balance/range of motion arms from the EXERT trial showed significantly less decline on a global cognitive composite score during the 12-month intervention than did similar adults with aMCI over a 12-month period in a large 'usual care' observational study (ADNI-1),” said lead study author Aladdin H. Shadyab, of the University of California, San Diego, and colleagues.
The researchers noted that regular, supervised activity was key to participant adherence, with most individuals maintaining high attendance over the year-long program.
Full disclosures are available in the published study.
Source: Alzheimer’s & Dementia