With the initial onset of my PMR flare I had fatigue like you could not believe. At times I had to take a 20 minute nap following my shower. My PCP found I was anemic and the cause was chased with no cause ever found and thus never treated. It eventually self corrected. Prior to the onset of PMR I had hypothyroidism and was stable on meds. With the onset of PMR my thyroid numbers ran off the rails and this too self corrected over time. I'm telling you this because both of those problems contribute to fatigue. Also, I am not on prednisone and I am fatigued most days. I suggest that the cause of fatigue for people with PMR is multi-faceted and not just one cause, not just the drug. If you haven't had blood work to check hemoglobin and thyroid numbers you might want to talk with your doctor.