I had the same question a while ago and a few people suggested bumping up the time to 45 minutes.

What I've noticed is that a timed 5 minute break is extremely short. It's pretty easy to keep the flow right through ... you can read HN or check which emails need attention with half a brain and keep the other half thinking about the task.

Or just go grab a cup of coffee. That is surely low-key enough not to break your flow right?

I think the keyword is: menial tasks.