MS Fatigue caused by lack of oxygen?

By February of my senior year in high school I was totally exhausted.  The Doctor diagnosed Anemia. (How would this correspond to Dr. Zamboni's opinion that the brain damage in MS is caused by the iron in refluxed venous blood). Nearly 30 years later a French Neurologist determined that the MS began when I was 18.  I was surprised because there were no neurological symptoms at the time, they would come 14 years later. There was only the fatigue. I know it's a bit creepy to think that my circulatory system is too small for  my body or somehow inadequate.  This implies that not enough blood flows into the brain to nourish it, in particular with OXYGEN, and that this is a major cause of the fatigue in MS. Maybe the entire circulatory system is "stunted", not just the veins which drain the central nervous system. (I have always assumed that nervous system damage meant that ordinary activities were more difficult to perform. That must be true as well, but lack of oxygen can certainly exacerbate the fatigue.)
 
The only time when I have the impression that my brain has been "oxygenated" is after a good swim when the blood circulation must be at full force.  My right side is handicapped, but I can do the crawl by using my good left arm to stretch out the right arm after which I use my back to advance the right arm and then turn to extend the left arm in good form The water holds up my body.  During the summer I can swim every day and that is the only time I can really exercise my entire body, as well as feel clear headed and alert.  An added plus is that the body doesn't overheat.