You can't really apply that kind of hard science to a fantasy medium. Superman is an alien powered by the sun, that's the entire explanation for his power set. The Flash doesn't burn calories to run fast, his abilities come from The Speed Force, basically an extra-dimensional energy field. Mutants literally have mutations that give them their abilities.

A lot of this sort of thing is just hand waved. Even Batman who is completely human and relies on physical training and technology, would dislocate his arms swinging around on grappling hooks.

I think for most people the interesting parts of comics are the character interactions and stories, not rigorous scientific explanation of how heat vision works.