Medical and surgical residents in hospitals should work no more than 16 hours without taking a mandatory five-hour sleep break, and they should get one full day off a week and at least two back-to-back days off a month, a panel of experts at the Institute of Medicine has recommended. The experts proposed work rules for physicians-in-training that are more restrictive than those that went into effect in 2003 but are widely violated. The panel also urged greater supervision of doctors in residencies.