Ive been told that WW2 Bomber PILOTS used to get enlarged hearts due to prolonged high alt oxy use.
Unlikely, I think. WW2 lasted 6 years, the altitudes were, what, not much more than 30K' (and that only in the later years) how much O2 use could there have been?
Compare that with blokes like me spending 32 years in unpressurised, or partially pressurised, military aircraft, pressure breathing above 40K' (IIRC) and no sign of enlarged hearts.
Also, no extra arms or legs from cosmic radiation. Half my flying was done in Victors and Canberras, well above F400 and often above F500. Not so many hours as you commercial chaps, I admit, but that's counterbalanced by the considerably less protected environment.
So what am I supposed to be suffering from?