Relations Between Cardiorespiratory Fitness and Cognition in Older Adults With Amnestic Mild Cognitive Impairment From the Aerobic Exercise and Cognitive Training (ACT) Trial: Sex Differences.

The study is cross-sectional, so it cannot show that fitness caused better cognition or that exercise will improve cognition. It used baseline data from a trial, not the trial's exercise intervention results. Global cognition was not associated with fitness after adjustment, so fitness should not be treated as a marker of overall cognition. The associations were significant in men but not women, and the study cannot prove that fitness is unrelated to cognition in women. The sample was highly educated, with an average of 16.9 years of education, and 87.3% White non-Hispanic, so it may not represent more diverse or less educated patients. Participants had amnestic MCI but preserved activities of daily living and no dementia, so the findings do not apply to more advanced cognitive impairment. 146 participants were eligible, but 142 were analysed. One participant did not complete exercise testing, two had difficulty with computerized cognitive tests, and one did not complete a premorbid intellect measure.

Do not conclude that aerobic exercise improves cognition in older adults with amnestic MCI. This paper analysed baseline fitness and cognition at one time point, not the effects of the exercise intervention, and global cognition was not associated with fitness after adjustment.