Normally I find it refreshing to read stuff from another field, away from the suffocating biases of many CFS researchers (and maybe my own too). But just read a 2007 review paper Physiological Basis of Fatigue that manages to say a lot about how deconditioning can cause fatigue - without backing it up with a single reference, which is odd given that other types of fatigue are well-referenced (180+ in total, zero on deconditioning). E.gs It's almost as if it's a consensus view that is excepted as self-evident without the need for any validation. A bit weird really. And a bit like CFS research too.