PS I always thought your avatar photo was of some exotic brown insect crawling up a tree but I just had a closer look and realised that it is a tanned man climbing a rock face! Is that you?
Um... yeah, that's me.
I go on gut feel too, and have yet to invest in a heart monitor, though I have taken part in a lab study, that measured my VO2Max and lactate levels at given power outputs, which I hope to use as a stick in the san for measuring my fitness in years to come, assuming \i get as serious about cycling as I appear to be at the moment.
Interesting insight into biological processes during exercise that study was.