To go opposite the 2 hearts, more lungs idea, due to the space constraints and affect on cda that poster mentioned, what about just having them have mutated mitchondria or something that are just wayyy more efficient and numerous than in a regular human? Something peripheral like that might be more plausible than something central like heart and lungs.
I think the idea of non reusable blood is a good one. Like he has 10w/kg but at the end of the day he bleeds it all out and goes into a murderous vampire rampage searching for more.
Two hearts basically makes no sense about how they would increase performance. It is a pump. How would a pump that pumps into another pump, that then pumps to the body work any better?
A huge heart or huge lungs would make sense, but it’s not very interesting
Rocket engines commonly have booster pumps before the fuel makes it to the rocket engine. While having two hearts doesn’t necessarily make much sense, its kinda an interesting idea if you’re into that sort of thing. It’s a fun thought experiment.
Here’s a schematic of the RD-180 that’s used in the Atlas V for reference: RD-180 - Wikipedia
