A Case of the Sleepys

I think, more than anything, the general lack of productivity in my writing life is the direct result of me being exhausted when I come home. I'm not really sure what's going on, since a 7 AM - 6 PM day is not really a long one, but I always tend to come home cranky and often headachy. Is it crazy to think it's because I work on the 19th floor? Every time I zip up the elevators I feel a little dizzy... Anyway, my usual remedy is to consume A) Coca Cola or B) Candy or C) Nap time, but I'm trying to escape the pull of those siren songs and find a healthier alternative. I have to say that exercise is pretty much out of the question, since I get home between 6 and 7, make dinner, and suddenly find myself with only a few hours to write before I need to do work stuff.

So I turn to you, fair readers: what do you to get energized and stay energized while writing?