Plus, older doctors did their internships when they actually got sleep during a 36 hour shift. Read the book Intern by Doctor X (Alan E. Nourse) which I read when it first came out in 1965. You will notice a lot about the advances in medicine in the decades since, but you should also notice how he was able to get sleep during those long overnights, unlike interns/residents these days.
And that's important. First that the older doctors do not fully understand what has changed over the years, and second is the entire issue of getting adequate sleep. Hell, I've known since high school that doing an overnighter and cramming for a final made no sense at all, and never did it.
I have been preaching the doctrine of Get Plenty of Sleep for decades now. Yeah, I know all too well that there are times when you will be unavoidably deprived of sleep. Such as when you have a new baby in the house. Such as when you have a job that has you working one night scheduled off at 10pm, only the flights run late and you don't get off until 1am, and still have to be back at the airport at 6am, but those are not every day occurrences. And when you're young, you can do it.
Once again, I believe that my lifelong commitment to getting enough sleep has paid off in my excellent health. I'm 72 years old, and I'm constantly astonished and dismayed at the many health issues that most people my age have. What is wrong with them? I ask myself. I do recognize that different genetics matter, but I'm still inclined to think that getting sufficient sleep is huge.