Habitual physical activity (HPA) as a factor in sustained executive function in Alzheimer-type dementia: a cohort study.

Evidence from studies on healthy older adults and mild cognitive impairment (MCI) populations suggests that physical activity interventions have a positive effect on executive function. In this study, we consider whether HPA is positively associated with executive function in Alzheimer's disease (AD). Eighty-two participants with a diagnosis of mild to moderate AD completed six measures of executive function. Objective measures of physical status were taken. In addition, informants completed questionnaires on the participants' HPA and other lifestyle factors. A composite measure of executive function was the primary outcome. A multistage multiple regression was used to determine how much variance HPA accounted for. The final model comprised disease severity, cognitive reserve, cognitive activities, neuropsychiatric status and HPA status. The final model accounted for a total of 57% of the variance of executive performance, of which HPA itself accounted for 8% of the variance. HPA status is associated executive performance in an AD population even after controlling for key covariates. The findings encourage clinicians to recommend HPA and its cognitive benefits to AD patients and their carers.