That's one reason why I like the idea of taking forced breaks; they give you a scheduled time to handle brief interruptions, and if you're fairly regular people can tune in to your schedule(e.g. if you're always "working" the first 50 mins of an hour and "resting" the last 10 mins, it's easy to know whether you'd be able to quickly answer a question). Of course, the forced breaks are another form of an interruption from flow; it's still a trade-off.