An increasing amount of studies show the beneficial effect of regular exercise on cognitive and brain functions and especially in the memory domain. Yet little is known of what happens within an acute bout of exercise and whether it would also yield cognitive effects. The literature clearly shows that molecules such as brain derived neurotrophic factor (BDNF) and endocannabinoids (mainly anandamide, AEA) are heavily involved in neural plasticity mechanisms and increase when we exercise hinting at possible mechanisms underlying memory improvement after exercise. We therefore focused on three main cognitive areas that rely on the hippocampus, one of the core organs involved in the memory domain, which is a very plastic structure and potentially sensible to exercise intervention. These focal areas were: associative memory, motor sequence memory and spatial navigation. All studies in this thesis are based on within-subject cross-over randomized designs.This is a global approach to this question combining cognitive testing, brain imaging and biomarker determination techniques, based on previous findings both in animals and in humans.