Yes. And yet it is tolerated in the medical profession for cultural reasons. The medical profession is a culture and although medicine is based in science, just like any culture there are customs, habits, and practices that are not necessarily grounded in scientific fact but exist for other reasons such as profit, tradition, formality, or even ego/machismo. Medical residents are used as almost indentured servants for hospitals under the auspices of "learning a lot in a short period of time" and the profession accepts that residents will work ungodly hours on insufficient sleep because, well, that's just how its always been done (cultural reason) and it is also treated as a rite of passage into an elite profession... I hesitate to say hazing but that term also comes to mind.

There has been pushback and efforts to reform this culture of overwork in recent years due to the recognition that less sleep = more mistakes = worse patient care, but by and large residents, and even many career hospitalists, are still used and abused as if the research on sleep deficit isn't clear and established. Hospitals have a profit motive to keep fewer doctors on staff, and the medical profession also strictly regulates the number of medical schools and their graduation output so as to limit the amount of practitioners to a certain amount... this is done to maintain scarcity (and therefore high salaries).

Ironically, limiting the number of practicing doctors to limit competition has opened doctors up to competition from nurse practitioners and other "mid level" providers who are succesfully lobbying states to allow them to independently practice with nearly the same responsibilities as doctors. The lobbying efforts are succesful because the lobbyists can point to "shortages" of doctors and also argue that nurse practitioners can do essentially the same job for cheaper --thus increasing access to health care and lowering the cost of care. (The fact is that nurse practitioners are not as educated or as competent as doctors, and the rapid expansion of NP schools has resulted in many new NPs with worse academic backgrounds than in previous decades, but their lobbying efforts are nevertheless effective)