This depends where you do your residency and what type of residency you match in. In some programs, you'll work close to 100 hours per week. In others, a 60 hour work week is average.
In my first year as a general medicine intern, I was on call every fourth night during my inpatient medicine rotation. This means being on call in the hospital on Days 1 and 2 for 36 hours. Then I work ~12 hour work days on Days 3 and 4, and then repeat the call process again on Day 5. When I was on call, I averaged about 1-3 hours of DISCONTINOUS sleep. Nurses paged me every 15-30 minutes with questions.
As an ophthalmology resident, my call is about every 5th day. I work ~10 hour days when not on call. Call nights are variable. Some nights I don't get called, but others I'll be up all night because of traumas and emergencies.
As for my colleagues in surgery and OB-GYN, they keep up the busy schedule for most of their training.
