Why did Anakin nor Obi-Wan get burned while they battled near lava in Star Wars: Episode III - Revenge of the Sith?
Normal humans would not resist it for so much time, is it because they are Jedi?
And what about Anakin after the battle ends? Burned and still alive...?
Echoing my answer on another stack...
The DVD commentary for Episode III (with producer Rick McCallum) explains this in more detail. In short, the blue haze you see is not only a repulsor field but it also creates a form of cooling for the Jedi:
Rick McCallum : This blue light around the bottom of the light and the platforms was added later on, in Production. George felt that at one point, that we needed to feel that there was some cooling effect, some kind of shield...a reason why our actors aren't burning up being around this intense heat so Roger Guyett and his team added these shields, this shield generator into this shots as another pass after they'd completed a lot of these shots...to help tell that story.
While they were near the lava, apparently, they generally stayed far enough away to catch fire from the ambient heat.
For information about how close you can be to lava without being injured in real life, see How close can you get to lava before burning? and How close can I get to lava and will it hurt or kill me? .
While Jedi do seem to have a higher pain tolerance (due to training and meditation), there is no evidence that Jedi have a lower flammability than other things. This seems to just be either a "physics of a galaxy far, far away", or a general conceit for the sake of the movie.
In the end, though, once Anakin has been defeated and left laying too close to the lava, he does catch fire.
Why does Anakin not die? Midi-Chlorians!
http://starwars.wikia.com/wiki/Midi-chlorian
Anakin was potentially formed from a mass of these microscopic life forms, so it is conceivable that these same life forms could keep him alive whilst not being strong enough to heal the wounds or regenerate limbs.
