Training Your Body to Write

I was listening to the Nerdist Writer's Panel talk to Glen Weldon about his new book Superman: The Unauthorized Biography.
He talked about the work habits he had developed and applied to writing this book. I found this almost metaphysical state that he reached in his writing life quite inspiring.

"Book was written on nights and weekends, in close to nine months. I went to The Writer's Workshop and they teach you that what you want to do is get up at eight o'clock and sit down at nine o'clock and from nine o'clock to twelve o'clock and you just stay at your desk and you write. Then you get up have lunch and edit.
"I tried it. You have two years of uninterrupted time to do nothing but write. And let me tell you, it works. There is something that happens. It is like you are training your body to get into this state.
"What I would find is that your body starts to realize that at nine o'clock you're going to being sitting down, so for the first 3 or 4 months the first 20 minutes are just woolgathering or wasted time. But gradually as you train your body you get to this point where you sit down, you start. You're off to the races. Because all the subconscious woolgathering has been going on while you're taking a shower while you're making breakfast as you are preparing to sit down. This was a very useful tool that does not work when you have a day job. And does not work when you have to come home at night and sit down when you've spent the whole day writing. So it's just catch as catch can. Staying up late and trying to work out because that does help a little bit, and just sticking to it."