Programming Sprints

Here is an interesting question, how many hours in a given week can you program? If you've got your head down and the code is just flowing out nicely, it isn't difficult to be very productive for hours at a time. But these sprints come in bursts. This code inspiration needs to come from somewhere. That is the other part of programming that isn't viewed as productivity. I'd say at least half, if not more, of a programmers time is devoted to reading. Either other code, a specific technology, technology in general, or something completely unrelated. Code sprints are spawned from doing this, not perpetually writing code.