It seems logical that letting doctors in training work marathon hours would be bad for them and their patients.

On the contrary, a new national study in Thursday's New England Journal of Medicine found that surgical residents who worked up to 30 consecutive hours were more satisfied with their training and patient care than residents restricted to 16-hour shifts. After a year, the two groups had no differences in rates of patient deaths or complications.

The study, led by researchers in Chicago and Philadelphia and presented this month, has reignited the long-running debate over "duty hours" of novice doctors, who spend up to six years in residency training.

The consumer group Public Citizen and the American Medical Student Association contend there are "egregious ethical violations" in the study - and in an identical, ongoing one of internal medicine residents led by University of Pennsylvania health policy researcher David Asch. Other experts have used the new results to opine about residency training reforms, medical errors, and physicians' quality of life.

In an essay with the study, Lisa Rosenbaum, a Boston cardiologist and correspondent for the New England Journal, said requiring residents to hand off care to another doctor rather than extending a shift interferes with their medical judgment: "We've created an educational system that compromises trainees' freedom to judge for themselves when their patients need them."

The duty-hours debate goes back at least to 1984, says Penn's Asch. That year, the death of an 18-year-old college student under the care of residents at New York Hospital set off soul-searching and eventual policy changes in medical education.

In 2003, the Accreditation Council for Graduate Medical Education (ACGME) restricted residents' work weeks to 80 hours. In 2011, ACGME went further, limiting first-year residents' shifts to 16 hours, and guaranteeing 14 hours off in between.

The reforms, however, have not been shown to improve patient safety and quality of care, and a few studies have found just the opposite.

That's why professional medical organizations and the federal government stepped up to fund the two ambitious national studies of residents' duty hours.

The surgical residency study involved more than 4,300 trainees at 117 accredited programs across the country. Half the programs stuck to duty-hour restrictions, while the other half received a waiver from ACGME to allow more flexible shift length and time off - but not longer work weeks. Although residents were aware that they were in a study, they were not given a chance to consent.

The fact that neither residents nor their patients consented to be in the study is unethical, Public Citizen and the medical students' association say in complaints.

"In our view, there is sufficient data to show that longer shifts are harmful to the residents, including [fatigue-related] car accidents and needle sticks," said Michael Carome, director of Public Citizen's health research. "We should not go back and try to change the limits that were imposed in 2011."

The ethics complaint was rejected by the ACGME, which said it had not waived "central requirements," including the 80-hour work week limit. The ACGME also said both studies' protocols were reviewed by ethics' evaluators at the lead researchers' universities.

The federal Office for Human Research Protections is still reviewing allegations from Public Citizen and the medical students' group.

Frank R. Lewis, executive director of the Philadelphia-based American Board of Surgery and senior author of the surgical residency study, said duty-hours restrictions have undermined another ethical principle: Patients' interests trump doctors' interests. That's why doctors have exposed themselves to diseases including AIDS in providing care.

"The doctor is ethically obliged to favor the patient," Lewis said. "That includes the issue of how many hours are spent taking care of patients. When the clock takes precedence over taking care of the patient, you overturn 2,000 years of medical ethics."

The lead author, Karl Bilimoria, a surgical-outcomes expert at Northwestern University's Feinberg School of Medicine, said the idea that residents often work to the point of extreme exhaustion "is a misconception."

"This study was about flexibility, not longer hours," Bilimoria said. "It's almost unheard of to work 24 hours without a break. There's always downtime and time to catch naps. We train our residents in fatigue mitigation techniques."