The Role Of Apolipoprotein ε4 Allele Carriage In Exercise-induced Cognitive Change

Abstract

Emerging evidence indicates that there may be substantial individual variability in exercise-induced cognitive enhancement, which likely contributes to the inconsistent findings regarding exercise and cognition across the literature. Previous research is inconclusive with respect to how genetic risk for Alzheimer’s disease (defined by apolipoprotein, APOE, ε4 allele carriage) modulates the relationship between exercise and cognitive health. PURPOSE: To examine the moderating effect of apolipoprotein E (APOE) ε4 allele carriage on cognition following a six-month exercise intervention. METHODS: Ninety-nine cognitively normal men and women (aged 60-80 years) were randomised to either six-months of high-intensity exercise (n=33), moderate-intensity exercise (n=34) or an inactive control group (n=32). All participants underwent verbal learning and memory assessment using the California Verbal Learning Test (CVLT) at pre- and post-intervention. A series of linear mixed-models were undertaken to examine the effects of a group*time, and group*time*APOE ε4 interaction term on repeated CVLT assessments. RESULTS: No effect of group*time was observed on any of the CVLT sub-scores. However, an effect of group*time*APOE ε4 was observed for CVLT learning (d=0.87, p < 0.01) and CVLT short delay recall (d=0.67, p <0.05). Post-hoc analyses revealed only carriers of the APOE ε4 allele received benefit from the high-intensity intervention, compared with the moderate-intensity and control groups. CONCLUSIONS: No changes in verbal learning and memory were observed from pre- to post-exercise intervention in the whole cohort. However, we observed that APOE ε4 carriers received benefit from the high-intensity exercise intervention in terms of improvement on tasks assessing memory and thinking. Our results indicate that individuals at greater risk of AD, and thus more likely to be experiencing a degree of cognitive decline, may benefit most from exercise.