Working hours: Get up earlier in general, in the OR around 6:30 sometimes before to set up. In residency generally out of the OR by 5:00 pm but highly variable depending on program. Then pre/post ops afterwards, talk to attending about the next days cases. I'd say 10-12 hour days are fairly common. It's what you do all day that's different. No coffee on rounds, no lingering lunches with the team. It's pure focus in the OR. While the surgeons are peeing/eating between cases, we are in the PACU with the last pt and then holding area seeing the next. No downtime between cases. Sometimes 45 minutes is all you get out of the OR all day, 15 in the morning, 30 at lunch. Pretty draining physically and mentally at first, but now in my CA2 year it's a lot easier.
Call: There aren't many q4 anesthesia programs (outside of ICU months) Mostly 4-8 calls per month. On call time can be up all night, or not depending on where you're at. Whenever the pager goes off though, it's to do something. No floor calls for Tylenol or Ambien so this is a big plus. It can mean a short procedure like an epidural or intubation on the floor, or it could be a complicated transplant that will have you up all night. In any case, you go home promptly in the morning meaning 7-8 am. No post call rounding. 30 hour calls from internship sucked bad. Of course, we come in late on weekday call so it's not even 24 hours.
Paperwork: A lot less. Preops are a pain anywhere, but it's still a lot less work than an IM admission. Post ops are about 1 minute long. Rounding on epidurals is very short. In the OR paperwork is charting vitals and medications, or at the very least entering notes and meds in the computer while it charts the vitals.
Tougher or not? In IM you'll have more patients, but it's harder to kill them. In anesthesia it's one patient at a time but it's easy to kill them. Afterall, an induction of general anesthesia is called a code in any other part of the hospital...
