Curious what field exactly, from rotations in residency and previous experience it seems to vary wildly.
The ED is non-stop action, sometimes more work than you should reasonably be doing probably. But in regular wards it seems that I had my work done about 3-4 hours into the shift most days and then I was just sitting around waiting for an admission or some results back.
Similar experience doing nursing in neuro before I got my MD, of the 24h hours I would reasonably work like 1/3 of that and most of the rest was downtime, usually I would sleep through most of the night too.