Haruki Murakami has made a name for himself over the past many decades as not only an acclaimed and prolific novelist, but also as a guy who rejects the traditional idea of a writer's life. He's written about his love of running, his workmanlike approach to writing, and his deep feeling of "being ordinary."
In his most recent book, Novelist as a Vocation, Murakami writes about balancing deep flow work with something that engages a different part of the brain:
The first step in my novel-writing process is, metaphorically, to clean off my desk. My stance is that I will work on nothing but the novel until it is completed, so I need to prepare. If I happen to be writing a series of essays, for example, I have to break it off, at least for the time being. Unless something really extraordinary comes along, all new projects are turned down. I’m the sort of person who when I throw myself into one thing, can’t do anything else. It’s true that I often work on translations while writing a novel, but those are done at my own pace and without any deadline, and I use them to give me a break from my writing. Translation is a technical process, so it uses a different part of the brain than creative writing. Rather than hindering the progress of a novel, therefore, working simultaneously on a translation can actually aid in the process by helping me keep my mental balance, a bit like stretching before exercising.
I find this fascinating and resonant. The conventional advice for deep flow work is to reject all distractions and focus on the task at hand. But Murakami's approach is to have a second thing to do, something that engages a different part of the brain.
When I'm working on a deep technical project, for instance, I "come up for air" by working on some piecemeal, smoother-brained tasks like backfilling comparison pages or clearing out some unused routes.