one of the most remarkable things i've found from intensive running training is how in tune i become with my body's needs. apparently, humans are alternately very durable and very delicate; when i don't ask much of my body, it says "sure, i can
give you 110% whenever you need me to", but as i get more and more involved, my resources are more constrained. i've started hearing more clearly the messages my body sends: "please eat protein now", "please eat sugar now", "you need to sleep for eight hours", "i have spare energy; go be active".
since i kicked my training schedule up to four days a week, i've been extremely worn out (physically) basically all the time. on a bike ride with zmccord to the climbing wall, i had to complain that he was going too fast - my legs told me if i asked them to pedal harder, the world would end. it seems like literally all the energy my body has for growth is going into being able to keep up with the marathon schedule - i have been doing the runs painfully but steadily (35+ miles/week!), and am totally depleted otherwise.
there's a wonderful sense of fulfillment in constantly living at the very edge of my capacity - i know and respect my boundaries, but not an inch of potential goes to waste. in past years when we used to have cluster/roselawn raves more often, i used to try to keep dancing until i couldn't stand anymore, just for the feeling of exhausted satisfaction - i'd say dedicated marathon training is just "legendary mode" of the same.
wikipedia notes that optimal levels of muscle glycogen, enzymes, antioxidants, and hormones, which are significantly depleted by intense endurance training, are achieved during a taper. so as i stop running as far in the last few weeks, i should expect to hear my body saying "spend more energy!" more often - and probably be careful to let it actually build up until race day.