I starve – because I want to. I am cold – because I want to be. I strain myself – for my own good, I say to myself. I am exhausted – because I need the challenge. I am left without energy and I still keep advancing till I break. That is all good and I have to keep it up if I want to keep dark thoughts at bay.
Diet, sports and self-constraint are beneficial things. And anyway: pain is just a bio-chemical process – ignore it!