Started as a junior Dr just before EWTD kicked in.
In later jobs I worked shifts but my first jobs were 24hr on calls. You'd start at 8am and be 'resident on call' overnight in effect that meant you just carried on working all through that day, the night and the next day!
Usually you'd find somewhere to kip for a few hours on a sofa in the mess or an examination couch in a clinic room (not a spare bed or the nurses would have to change it). If the nurses liked you enough they might bring you a tea and a blanket. You would have the dreaded bleep though and I never slept much for fear of missing a call.
If it was a weekend resident on call you'd start at 8am Friday and work until 6pm on Monday. You were on duty on the hospital site the whole time with much reduced back up from other Drs and might catch a few hrs sleep but that's all. Looking back now it was hugely unsafe.
By the end of one of those I'd usually feel kind of shell shocked and like the walking dead but even then you had to come in 8am the next day.
It was a system designed in the olden days when Drs were really 'on call' and were mostly sleeping at night or doing their own thing at weekends and not getting called but by the time I did it the workload had increased so that you were mostly working with your bleep going incessantly.
Thank God they did away with that stuff. We wore it as a badge of martyrdom at the time but some Drs died driving home after such on calls and I dread to think how many patients had poor care from exhausted Drs. I had friends who burnt out and left after a year or so.
To add insult to injury we were not even paid properly for it. We had an 'on call supplement' which was much less than the hrly rate for the day job as again it assumed you would not mostly be working just available to be called. This is what led to the claims that Drs were paid less than cleaners. For those overnight hours it was true.