Let me begin by saying that, when I was 20, I would have laughed at the idea that I would ever write something like what follows below . . .
I've learned, over the last eight years, that my reading days have very different rhythms, determined, in large measure, by what I do in the first two hours I'm awake. I've tried to figure out a phrase to describe my reading behavior, and all I've come up with is this: I'm a "momentum" reader. In order for me to read a lot in the course of the day, I need to begin reading early in the day and get a chunk of reading finished.
When I wake up at 5am and read until 7 (refilling my coffee cup and noshing throughout), I tend to finish up the day pushing through 100-200 pages. For some of you, that's not a lot of pages, but I'm a slow reader. Those two hours in the morning seem to set my mind in a particular mode for the rest of the day, and typically I pick up my reading after dinner and read through the night. I feel like I gain momentum in those first two hours of the morning that I carry through the rest of the day.
By contrast, if I don't have those early hours--if I am distracted, for some reason, by work or other issues and don't read--I find it difficult to start reading later in the day. Certainly the issue(s) I'm working through can distract me throughout the day (and sometimes beyond). Many times, however, I have been able to resolve those issues during the course of the day, and still cannot settle myself into reading in the evening. I might wind up reading only 20-30 pages, and struggle to get through those pages.
I learned some of this in a general way after my first son was born near the end of grad school. Before that moment, I often spent full days--literally from when I woke up until 7 or 8pm--reading and/or writing. I could keep that up for days, and did so happily. After he was born, it was no longer possible for me to work non-stop throughout the day. As anyone with children knows, the schedule of a baby or toddler is broken up into short chunks of time: short naps, short periods happily entertaining himself in the crib/other plastic baby holder product, short periods of changing diapers, feeding, and getting him to bed. As I completed my dissertation, in short chunks of time, I realized how difficult it is to work that way. Long periods of work time, when I could gain momentum and get into the rhythm of my work, were productive; short periods of work time were jarring and disconnected.
The boys are much older now, and occupy themselves independently (mostly), but when it comes to reading, I need now, like I did then, to gain momentum that I then maintain for the day.