Multiple sclerosis (MS) is a progressive inflammatory disease of the central nervous system that normally leads to impairment and persistent disability at a rather early age. The observation that physical stress can lead to the onset of reversible neurological symptoms has in the past led to patients being discouraged from doing sports. We investigated the current status of research and conclude that this advice may be as incorrect for a majority of MS patients as recent recommendation which encourage individuals with MS to engage in all kinds of physical activity.