"the more popular intent of the phrase is to mean "fatigue resulting from stress on the Adrenal Glands"
So it's not about science, it's about popularity determining what something means?
What do you mean "stress on the Adrenal Glands"? Does that mean the adrenals top out at 80 mph, but the brain wants them to go 100 mph, and in trying to go faster, the adrenals start petering out and now can only go 40 mph? Or is it the adrenals are able to keep going it's top speed of 80 mph, but since the brain wants to go at 100 mph, it feels like the adrenals are only going 60 mph?