This morning i was having a bit of trouble with fatigue. Caffeine wasn't making any impression on it, nor carnitine nor tyrosine. I decided to try some nicotine, and all of a sudden i had an urge to get out of my chair and work on the powder room some more. The rest of the afternoon flew! I finished removing the wallpaper from all of the west wall i could reach without a ladder, and called it a day.
When we're feeling more-or-less GOOD, with "normal" energy levels, work and exercise feel good too. People who don't have chronic fatigue issues probably only experience this kind of weariness, which carries with it the satisfaction of accomplishment and the promise of good rest and returned vitality tomorrow. This is the way it should be. Unfortunately, some don't share this experience -- theirs is completely otherwise.
And this is one of the reasons that normal people can't empathize with "chronic fatigue" sufferers. Hell, even the name of this problem is felt by its victims to be a minimization of the disease; while some have widely-varying day-to-day energy levels, others are completely prostrated by the lack of available energy for the essential activities of living. Their lives are devastated by inability and they're not even taken seriously by much of the medical establishment -- they're constantly told that they're malingerers and it's all in their heads.
So many medical problems have fatigue as a significant symptom, i can imagine that pinning down the diagnosis IS tricky. As a hypothyroid, i've always had energy issues, and my fatigue has waxed and waned in a manner not at all predictable. Fatigue crops up in association with neurological problems, too, and with mitochondrial issues and in concert with difficulties in energy-retrieval and ... innumerable others that i'm not qualified to list.
In the last few decades, CFS/ME [(Chronic Fatigue Syndrome/Myalgic Encephalomyelitis) and its aliases post-viral fatigue syndrome (PVFS), chronic fatigue immune dysfunction syndrome (CFIDS), or by several other terms] HAS gained some ground, though the whole situation is far from well-defined OR understood. The sufferers and their doctors have amassed quite a few techniques for improving energy and quality-of-life, and i'm hoping to be able to pick their brains for some good pointers. It's turning out to be a very interesting study!
You see, i WANT to be able to enjoy more afternoons like i did today -- expending some energy i actually have TO SPARE, and accomplishing things.