EXCEL: Exercise for Cognition and Everyday Living for Seniors With Memory Complaints

Alzheimer's disease (AD) is a major health issue in Canada; it affects over 8% of the population aged over 65 years. Persons with AD have a reduced quality of life as they become dependent on others for activities of daily living (ADLs). This problem of loss of independence - functional dependence - is one focus of this grant application. It is projected that by 2020, Canada will have well over 10 million seniors with moderate to severe functional dependence. Functional dependence was the most significant contributor to an annual cost of dementia that had already reached $4 billion in the 1990s. Mild cognitive impairment (MCI) is a well-recognized risk factor for both AD and functional dependence. Within the broader assessment of cognitive function, the literature suggests that executive functioning - the ability to concentrate, to attend selectively, to plan and strategize - is a robust cognitive predictor of functional status in seniors. Specifically, Royall and colleagues demonstrated executive functioning independently explained 43% of the functional status in community-dwelling seniors dementia. The researchers will investigate executive functioning in seniors with MCI. Randomized trials of various exercise interventions have proven that exercise has many systemic benefits. Data are emerging that physical activity may improve cognition - specifically executive function - in healthy adults. The researchers' own pilot data suggest that resistance training in seniors may improve executive functioning as assessed by neuropsychological tests and neuro-imaging. However, at present the Cochrane Database of Systematic Reviews indicates there are insufficient published data to guide exercise prescription to prevent AD. In persons with MCI, no published studies have reported on whether physical activity can improve executive function, or delay its decline and thus, prevent or delay the onset of functional dependence (and later, dementia). Therefore, among seniors with