I'm making a character and trying to be biologically accurate. The said character has transfusion-dependent anemia (from Gunther disease/congenital erythropoietic porphyria) so I suppose exercising would be hard by default, but what are some other conditions that would make physical training unhealthy? Ideally, I'm trying to make it so even light exercising is bad, but severe would cause vomiting/fainting/etc.
I posted this question on biology, but someone suggested I try asking here instead. I think that the question is less relevant there, so might as well ask here since I didn't get an answer anyway. I apologize for asking the same question twice.