The focus is really about human endurance in general, but as it happens the examples used are Ironman and the Race Across America:
http://www.radiolab.org/2010/apr/05/limits-of-the-body/
I'm not completely sure I agree with the ethics of the winner's team. Your man's so exhausted he's hallucinating badly and it's your job to keep him in one piece? Just tell him the monsters he's seeing are real and he needs to ride quicker to escape them. Problem solved!