Aims: * Investigate the brain's neurophysiological responses and memory effects following a training intervention and, separately, sleep, in the form of a power nap, in individuals with MS. * Examine whether these effects persist beyond the few days previously observed in healthy individuals by implementing a longer-term intervention. * Explore whether the training effect is influenced by disease activity in the brain, such as during relapses and during immunosuppressive treatment. * Assess whether the presence of abnormally reduced cognitive endurance (fatigue) affects the impact of the intervention involving exercise and sleep. The study is based on documented positive effects of physical activity and sleep in both young and older adults, as well as in individuals recovering from stroke. The research thus offers promising perspectives for broader applications within neurorehabilitation, and particularly for MS, as the disease is associated with functional impairments. At the same time, both physical exercise and sleep represent meaningful interventions that should be thoughtfully integrated into rehabilitation strategies.