Age-related cognitive decline : the roles of physical activity and the apolipoprotein E e4 allele

We examined the effects of physical activity and the apolipoprotein E e4 allele (APOEe4) on age-related cognitive decline amongst a sample of cognitively normal middle-aged and older adults. Forty-seven participants (76.6% female; 23.4% male) aged 50-71 at baseline (`M` = 60.0, `SD` = 5.8) wore an accelerometer to record total weekly level of physical activity. Participants also underwent APOE genotyping and annual cognitive tests assessing long-term memory and learning, working memory, and executive functioning through the Tasmanian Healthy Brain Project. We conducted a series of three-way mixed analyses of variance to test for interaction effects between physical activity status (active; inactive), APOEe4 status (carrier; non-carrier), and assessment phase (1; 2; 3; 4) on performance on each of the cognitive tests. For all cognitive tests, there were no consistent effects of physical activity, no consistent effects of APOEe4, and no significant interaction effects between physical activity, APOEe4, and phase of assessment. Findings suggest that physical activity, APOEe4, or combinations of the two do not influence nonpathological age-related cognitive decline. Future research would benefit from examining the possibility that APOEe4 may be detrimental to cognitive decline for individuals that carry two copies of the allele, and from examining whether lifetime levels of physical activity or specific types of physical activity influence age-related cognitive decline.