Exercise therapy may have a positive effect on MS-related fatigue, however, the findings of a systematic review show the impact of exercise can be highly variable.
"I think the problem with in the field of fatigue is that we still don't know how to measure fatigue or even characterise it; for example mental/cognitive vs. physical (exercised-induced or temperature-sensitivity) or fatigue related to low mood or sleep deprivation. Sleep-deprivation is a common problem in PwMS and relates to many issues that are often relatively easy to manage, for example nocturnal spasms, pain and nocturia (getting-up to go to the toilet due to bladder problems). I think it is time we sorted this mess out."
Andreasen A, et al. Mult Scler. 2011 Apr 5. [Epub ahead of print]