Perennial questions: on fatigue, on iron, and on anemia.

Introduction Some questions recur regularly or seem to endure forever. This may be partly because we still have a lot to learn. Questions recur on fatigue and what to do about it, on the role of iron therapy for this or that, and on the nature and definition of anemia. In light of recent questions like this, I cover here new developments in these fields, developments relevant not only to medicine in general, but also to sports medicine and athletes.