That was a great little video. The only thing I'd like to add is that in addition to a CFS person not being able to produce enough energy for their basic functioning making them feel tired, at least from my experience, is that simply feeling unwell in whatever way that might be, even say being in pain, also consumes alot of energy. This magnifies and compounds the problem. Being sick consumes vast quantities of energy. When I am not doing well at all, and suffering, I can feel my body burning up tons of energy, even if I'm simply lying down, half asleep. I actually think a sick person even lying down (and I mean quite sick, and for me pain as well) burns at least as much energy as a healthy person engaged in heavy exercise. I've both exercised heavily in my life and also have spent many many hours lying in bed in an unwell state, and actually think for me, I burn more energy simply existing as a sick person, than I do, feeling ok, engaged in heavy exercise.