How do you program for 8h in a row?

I agree with the author that time spent coding isn't a goal in its own right, any more than counting minutes spent at the gym. But if you thrive on programming, it's a net positive in your life, you're meeting your obligations, and you happen to spend large amounts of time doing it, fantastic - no one can complain! If you're putting in 12 hour days to please a boss, not get fired, or to compete with colleagues, you're playing a totally different and rather unfortunate ball game.