Ditto what the previous poster said. It depends on what rotation you are on.
I am half-way through our eight-week third-year surgery block and find that I have to get up at around 4:45 in order to shower, shave, brush the fangs, and get to school early enough to write notes on the patients I am assigned before rounds. We round at about seven and then we either scrub in on a few surgeries or attend various clinics until at least 3:00PM. Most days we have some kind of lecture or professor's rounds in the afternoon. Then we do a "mini-round" with our residents and usually finish by around six.
We also have call about once a week.
As you can see, this is a lot of hours. The key is to go to bed early. Also, you have to find some "slack time" here and there. We have, for example, something called "Comprehensive Care Clinic" once a week which is scheduled, usually, from 1PM to 5PM. Even if I only have one patient scheduled or finish wicked early, I still try to "avoid" the wards until five. And I might "vanish" at 2 PM four times a week to lift weights for half an hour.
Point is, there is some "down-time" during the day. You just got to ask yourself how eager you are to do scut work. The first week of the rotation I didn't realize this and was running myself ragged.
Additionally, if things are slow, I will park myself in the conference room on the floor and study my surgery review book. I call this "hiding in plain sight." The residents know where to find me and if they need anything done I am at there disposal without being in their faces.
I can't say I've worked any 80 hour weeks. Mostly between sixty and seventy.
Some rotations are like nine-to-five jobs. Pediatrics and Psychiatry come to mind.
Just a note about the 80-hour limit. I find it laughable that the "old-school" think that 80 hours a week isn't enough time adequetly train residents. I think the real problem is that modern hospitals are so inefficient that much of the residents time is taken up wrestling with paperwork instead of training. I don't know the solution to this, of course, but seriously, I bet a study would find that lack of sleep makes learning impossible so anything over eighty hours is academic.