Whatever Doesn't Kill You.

I am starting to feel like someone's science project. Measuring my sweat loss, calculating my lactic threshold while contemplating my proper nutritional needs. This morning I suffered through the last couple miles of my 19.5 mile run. Suffered like I felt like some organ was going to stop working inside of me.   Don't get me wrong, I get off on the work that goes into training for these things, but sometimes I really step back and wonder why am I doing this to myself?  Marathon training is grueling.  Most marathons are run in the Fall, and that puts us out on the roads training through the heat of a long summer, and early fall.  We were lucky enough to get 80 degree temperatures in March this year, and so I am lucky enough to be training for an October marathon in 8 months of heat.  I am not trying to complain, but I guess the question is what do I get from this?  I am a middle of a packer, who will never win any money, or really any sort of prize for my running.. So really, why did I chose this goal?