Michael M.E. Johns, chancellor of Emory University in Atlanta, and chairman of the Institute of Medicine committee that created the report, said they propose revisions to medical residents' duty hours and workloads to decrease the chances of fatigue-related medical errors and to enhance the learning environment for doctors.

The report does not recommend further reducing residents' work hours from the maximum average of 80 per week set by the Accreditation Council for Graduate Medical Education in 2003. However, violations of the current limits on duty hours occur frequently and are under-reported, the committee found.

The report recommends that rather than reducing the maximum number of hours that residents can work without time for sleep to 16, increases the number of days residents must have off and restricts moonlighting during residents' off-hours.

Financial costs and an insufficient health care work force are the biggest barriers to further revising resident hours, the report noted.

To implement the report's recommendations, some of the work currently performed by residents would have to be done by others. That would cost roughly $1.7 billion annually, or less than half of 1 percent of what Medicare spends annually, the report said.