"I will be off Methylprednisolone in 6 days and will keep up the Actemra infusions. I have good levels but just get so exhausted. I can do something, but then drag around like a zombie for 3 days. No one can say if that's the Actemra or the PMR. I felt better a year ago!"
-----------------------
Whenever I read about fatigue being described like this ... I immediately think it might be related to a low cortisol level. It seems to happen when people are at low doses of Prednisone while trying to taper off.

It has been shown that cortisol levels should increase with moderate amounts of exercise. The adrenals are suppressed by long term prednisone use. I wonder if adrenal suppression is responsible for excessive fatigue and slow recovery times after exercise??

I recall feeling the same way when my cortisol levels were low. After my adrenal function improved so that more cortisol was being produced ... I could exercise longer and recover faster after exercise.
https://www.rupahealth.com/post/exercise-cortisol-how-exercise-affects-your-stress-hormone
My exercise tolerance didn't improve as soon as I tapered off Prednisone. It did improve with time as I exercised more. Also, my adrenals were capable of producing more cortisol with time after I tapered off Prednisone.