Gosh. That would be totally impossible for me, it would completely break my concentration. But then, I generally do not take coffee breaks or lunch breaks at work, because working a day straight is about four times as productive as breaking the day up every time I get some flow going.
I think it works for me because I cannot do any one thing for so long. I naturally multitask (probably ADD or something, never got tested as a kid, never gonna be). If I sit to work on a novel and do nothing else, eventually I'll drift off mentally and not go back, self-imposed writers laze. When given something equally engaging to focus on from time to time, I go back to my story with a fresh mentality every couple of minutes.
.... I feel I should also mention the TV runs in the background so I don't miss my favorite shows