From the article, a fair few internal interruptions are procedural, things like writing a commit message. I took a big point as being that you should design your work processes to help maintain flow.
You said this so much better than me! These were the ones I was thinking more of when writing my comment, rather than all the distractions of a noisy brain. I agree entirely with folks here that those are not in any way easy to overcome. (Though still easier to overcome in the absence of lots of external interruptions.)
