I worked in the NHS before the hours were capped and my God how more people didn't die was more by luck rather than anything else.
A House Office as they were called at the time, could easily start shift at 9am for rounds (In reality s/he would have been in a few hours earlier to check notes, learn what new patients had been admitted/ chase blood results etc)
Following rounds they would have piles and piles of paperwork to fill, more results and test to chase.
In the mean time people like me (ex-Nurse) would be bleeping them constantly to come and fill in discharge notes/prescribe discharge meds so that we could get them to pharmacy, because we were getting shouted at by Bed Managers, who were getting pressure from A&E/ ITU etc.
If this was also one of there on call days they would also be getting bleeped to review new patients, fill in their prescription sheets, order their tests, re-cannulate difficult patients, pass catheters, take arterial bloods, speak to families etc. (Yes Nurses can and do, do these things but if for what ever reason you can't and the local Nurse 'wizard' ie: one who always succeeded one of my colleagues could pass an NG tube on anyone, another get blood from a stone, you first had to call the HO even though you knew they had less experience than you)
At some time between 5 and 7 they would then take over from the teams who weren't on call. (at the time we had 4 general medical teams caring for 120 patients) so one HO was the first point of contact for any of the Nursing staff when any of those patients needed any medical rather than nursing care.
Even on a 'good' night most would be lucky to grab 2-3 hours sleep and as they couldn't leave the hospital this would be in a on call room which were usually small, airless and never ever quiet. If very luck there might be half decent showers and then start again. If it was their weekend on call this could carry on from Friday 5pm until Monday 9am, when they would still be expected to work their 'normal' day.
It wasn't unusual to find HO's crying with tiredness; terrified that they were going to make a mistake and shaky from the amount of caffeine they'd consumed.
While its not hugely better now it is better, we as a people should be supporting improvement, and if they have to strike to get it, so be it.