Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive memory and neural plasticity loss, affecting the hippocampus and neighbouring entorhinal cortex. The major genetic risk factor for the common late-onset form of AD is the APOE (apolipoprotein E) gene e4 allele (carried by 20% of the population), while the most common e3 allele (60% of the population) seems to be neutral concerning AD. Recently, several lifestyle factors have been identified as possible regulating or therapeutic factors, which may influence the onset and progression of the disease. Among these, physical activity emerges as a highly relevant variable to be investigated. Indeed, regular physical exercise improves memory functions by increasing neural plasticity in the hippocampus, where neuronal loss due to AD appears first.

Here we tested the effects of a single session of medium-intensity physical exercise on declarative memory in two groups of healthy young participants, one at high genetic risk of developing AD (APOE-e4 carriers) and one at low genetic risk (e3 homozygous). So far, we tested 18 high-risk and 16 low-risk participants in a within-subjects design comprising one exercise and one rest visit. During each visit, participants performed the encoding part of an associative memory task in the morning, followed by the exercise or rest session, after which participants had to retrieve easy and more difficult associations. All memory sessions were performed in the fMRI scanner.

Preliminary results showed a clear effect of task difficulty, but so far, no effect of genotype or sport.