Since 2003, when an 80-hour-a-week cap was placed on the nation's medical residents, many older physicians have worried that the next generation of doctors won't have seen enough patients and done enough procedures. In response, some residents complain that working so many hours without sleep diminishes their ability to absorb lessons and avoid errors. Now, the group that governs residency programs is considering even tighter limits, possibly down to 60 hours a week. Now those older doctors argue that constant baton-passing by shifts of residents can disrupt patient care.