To be honest, I am sceptical about what regular bloods would tell you. The last time I had my bloods done it wasn't for training purposes, i'd been experiencing some post-operative pain and was worried about startng a mega-tour in a few days time. The results, in the words of the nice physician at the Toronto teaching hospital I visited, were "pristine". Absolutely everything was smack in the middle of the normal range.

The funny thing is, I wasn't especially fit at the time. Overweight, and at the end of a five-day binge with some friends that had involved far, far more alcohol than was good for me. It reminded me of an intensive care doctor i used to work with, who used to tell his students "most of our patients die with their electrolytes in perfect balance".

Don't worry about this stuff. If you have a problem, get checked out. If not, you don't have a problem.