A significant obstacle in securing medical acknowledgement of fatigue is the lack of comprehensive and accurate biomarkers. A significant obstacle in securing medical acknowledgement of fatigue is the lack of funding for a comprehensive research program for accurate biomarkers.
Is fatigue a condition? Bit weird to frame it this way. It's a symptom, and symptoms can only be self-reported, by definition. It's the most common symptom in all medicine, and yet oddly enough, it's largely doubted, even disputed. Which is incredibly odd: it's the most common, and yet that makes it even more disputed, with the common dismissal of "everyone gets tired", coming from people who are familiar with sick people so weak they cannot even turn in bed. Because what they don't understand, they are taught to dismiss, which is the real underlying problem. And there is a big question of what if there is no biomarker for fatigue? No single, unique one anyway, which is the demand from the medical profession, because they found many of those and cannot think outside of that paradigm. Sometimes when a system is overstressed, in the sense of overreaching its ability to perform, it just performs less and less, then breaks. That is the marker in itself: the loss of performance. Then the break. We see both. And they are both disputed, simply because in biology, sometimes systems repair themselves. Just the same with materials and stress testing, if you try to bend something, say the wing of an airplane, to its breaking point, you may see a bit of heat, you may see some microfractures, if you look deep enough, but until it just breaks, you will basically not see anything significant. There is only the sum of many small things reaching their breaking point. Then it will snap, but it will have been in a weak state before then. And in medicine, the general thinking aligns with stressing it even more, with applying more force, which is plain silly. It's sad but it's really the lack of holistic thinking that sinks everything, with holistic thinking in medicine having been instead taken over by blatant quackery. And the fact that there is no math to solve disputes. In all other disciplines math is the thing that ends debates, and medicine just doesn't have it, and there is no plan B when plan A fails, the only accepted plan.
Project website here, https://idea-fast.eu/ We have a thread for one of their publications, Assessing fatigue and sleep in chronic diseases using physiological signals from wearables: A pilot study 2022 Antikainen et al It is noted in the above thread that one of their exclusions is CFS.