Fatigue is one of the most frequent symptoms in people with MS and can occur in more than 65% of cases. Fatigue is defined as "the subjective lack of physical and / or mental energy" perceived by the person affected by MS and that can limit or interfere with their daily activities. Although the exact cause of fatigue is unknown, it is being investigated and is believed to be the result of a combination of factors. http://www.observatorioesclerosismultiple.com/es/vivir/fatiga/11-recomendaciones-para-combatir-la-fatiga-con-em/