Fatigue in the muscles

Hello.
Still many days, it's difficult to walk more than to the grocery store and about the house. My muscles get weak.

Could you explain ( if there is a clear way ) biochemically, why the muscles become weak in those with adrenal fatigue (and including for most thyroid, as high levels of cortisol seem to create high levels of RT3.

Being hypoglycemic too, even when my blood sugar levels are within normal readings and eating properly, why is the muscle fatigue still always there. Does it evolve around the mitocondria or just an overall large assembly of metobolic pathways?

Thank you.
Paulette Tweet