That is a very good question about the exercise. I suppose the best answer would be that we do what we can, without over doing it, since doing too much can lead to a couple of very bad days. Try spacing your exercise out. Do a little, then rest until the muscles have recovered, then do some more. Spread your exercise out through a whole day, little at a time. That might keep muscle tone up, but hopefully won't fatigue the muscles or bring on a worsening of MG symptoms.
Anybody else got a better idea? I'm open to suggestions.