Don't tell anybody this, but I always take a 15 minute nap in our break room after lunch everyday at work. It really helps me get back to focus for the rest of the day when I'm coding.
Maybe the fact that you feel like you have to keep this a secret is a clue that you're not at the right place.
Well I like where I work, but the only problem is that the old people don't believe in naps. They prefer the 9-5 mundane corporate environment despite the fact that we're a startup.