Intended for healthcare professionals


Extended work hours increase risk of harm, regardless of resident physicians’ experience levels

BMJ 2023 ; 381 doi: (Published 13 April 2023) Cite this as: BMJ 2023;381:p838

Linked Research

Impact of work schedules of senior resident physicians on patient and resident physician safety: nationwide, prospective cohort study

  1. Charles A Czeisler , Baldino Professor of Sleep Medicine , director, Division of Sleep Medicine , chief, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology 1 2 ,
  2. Matthew D Weaver , instructor in medicine , associate epidemiologist, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology 1 2 ,
  3. Christopher P Landrigan , chief, Division of General Pediatrics , director, Sleep and Patient Safety Program , William Berenberg Professor of Pediatrics and Professor of Medicine 3 2 1 ,
  4. Laura K Barger , assistant professor , associate physiologist, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology 1 2
  1. 1 Harvard Medical School
  2. 2 Brigham & Women’s Hospital
  3. 3 Boston Children’s Hospital

When resident physicians work shifts of extended duration, the risks of patient harm and occupational injury increase, even among experienced resident physicians, write Charles Czeisler and colleagues

The working hours of resident physicians have been controversial since William Stewart Halsted, a cocaine addict 1 who became the first professor of surgery at Johns Hopkins Medical School in 1889, first required training physicians in the US to work unlimited hours. They were obliged to remain in the hospital 24/7 throughout their training years (hence the term “resident physicians”). Ever since the patient safety hazards associated with 24 hour shifts were first documented 50 years ago, 2 multiple reforms have been attempted. In 2009, the National Academy of Medicine recommended a series of reforms for all resident physicians. 3 However, the Accreditation Council for Graduate Medical Education (ACGME) failed to adopt most of these recommendations, such as the limit of four consecutive night shifts, 12 hours off following night shifts, and 24 hours off every week. Although the National Academy concluded that extensive evidence supported a 16 hour work-hour limit for all resident physicians, the ACGME only implemented the recommended limit of 16 consecutive hours caring for patients for first year (PGY1) resident physicians. 4 PGY1 residents account for ~21% of resident physicians, so that nearly 80% of resident physicians could continue to work 28 hour shifts. The ACGME noted that most of the evidence on which the National Academy based its recommendations was came from PGY1 resident physicians, and posited that one year of experience would somehow overcome the adverse impact of fatigue on patient and occupational safety. 5

Our recent study 6 found that more experienced resident physicians (PGY2+) working shifts of extended duration (≥ 24 hours) and/or long work weeks were more likely to sustain workplace injuries, reported a higher rate of near-miss motor vehicle crashes, and were more likely to commit medical errors, including serious errors that resulted in harm, adverse events, or fatal adverse events to patients. Our findings show that experience fails to overcome the detrimental impact of extended work hours. This is consistent with other studies which show that even experienced attending physicians have increased rates of complications in surgeries the day following an overnight call if they did not get sufficient opportunity for sleep. 7

The ACGME’s failure to implement most of the National Academy recommended work hour reforms in 2011 exposed patients and physicians to considerable hazards. 3 6 Even after the ACGME announced plans to limit PGY1 resident physicians’ shifts to 16 consecutive hours (to counter public opposition to > 24 hour shifts 8 and stave off potential Congressional action), the efficacy of the intervention was undermined as hospitals were still allowed to schedule nearly 80% of resident physicians to work extended duration shifts. This led to flawed studies evaluating hospital-level outcomes when only around 21% of resident physicians had limited work hours. One study of PGY1 surgical residents used serious surgical complication/mortality as its primary outcome, but PGY1 residents seldom operate on patients and so would have little impact on this outcome. 9 Another study used a non-inferiority design that was not powerful enough to detect potential harm. 10 11 Nonetheless, in 2017 the ACGME quietly rolled back the inadequate reforms it had implemented in 2011, allowing hospitals to schedule all resident physicians to extended duration work shifts, despite their documented hazards. 12 13

The US public disapproves of resident physicians working extended duration shifts, and only 1% approve of shifts longer than 24 hours. 8 In other parts of the world, physicians are trained effectively while working safer hours. 14 Resident physician work hours have been limited to 16 consecutive hours since 1985 in New Zealand. The European Working Time Directive and the UK’s Working Time Regulation nominally limit day shifts to 13 hours, night shifts to eight hours, weekly work hours to 48, and require 11 hours off per day.

The ACGME should implement evidence based comprehensive fatigue risk management policies that apply to all resident physicians, regardless of their experience. These policies should include safer work hour limits, screening for sleep disorders, and accommodations for those with disabilities and medical conditions that affect their ability to work non-standard hours. 15 Those policies should limit weekly work hours and eliminate extended duration shifts. As the National Academy advised, resources are needed to avoid increases in workload when resident physicians work fewer hours. 3 Medicare already provides $10-12bn annually to teaching hospitals for resident physician training. Rather than requiring new funding, Congress could restrict use of this funding for teaching hospitals that implement the safer limits for work hours recommended by the National Academy, and actually spend those currently unrestricted dollars on resident physician training rather than elsewhere. Restricting use of this funding that Medicare already provides for resident physician training would be sufficient to fund meaningful work hour reforms. 3 Such reforms should include supporting unit clerks to assist resident physicians with burdensome paperwork and patient placement, implementing comprehensive evidence based handover programmes to reduce medical errors, hiring physician extenders to pick up work load as resident physician work hours are reduced, and providing comprehensive resident physicians with education in sleep health and screening for sleep disorders. The evidence shows that failure to do so will increase risks to both physicians in training and their patients. 6


  • doi: 10.1136/bmjmed-2022-000320
  • Competing interests: LKB reports support from the National Institute for Occupational Safety & Health, the National Heart, Lung, and Blood Institute, Puget Sound Pilots, and Delta Airlines, through Brigham and Women’s Hospital and Brigham and Women’s Physician Organization, and personal fees from Boston Children’s Hospital, University of Helsinki, and the AAA Foundation. MDW reports grant support from the National Institute for Occupational Safety & Health, National Heart, Lung, and Blood Institute, and the Centers for Disease Control, as well as consulting fees from the Fred Hutchinson Cancer Center, National Sleep Foundation, and the University of Pittsburgh for activities outside the submitted work. CPL reports personal fees and other from I-PASS Patient Safety Institute, personal fees from Missouri Hospital Association/Executive Speakers Bureau, outside the submitted work; and in addition, CPL has received monetary awards, honoraria, and travel reimbursement from multiple academic and professional organisations for teaching and consulting on sleep deprivation, physician performance, handoffs, and safety, and has served as an expert witness in cases regarding patient safety and sleep deprivation. CAC reports grant support from National Institute of Occupational Safety and Health within the US Centers for Disease Control and Prevention, the Agency for HealthCare Research and Quality, and the National Health Lung and Blood Institute. CAC serves as the incumbent of an endowed professorship provided to Harvard Medical School by Cephalon Inc in 2004, which provided institutional support for this work. He has received additional support from Delta Airlines, Jazz Pharmaceuticals PLC Inc, Axome Therapeutics Inc, Philips Respironics Inc, Puget Sound Pilots, Regeneron Pharmaceuticals, and Sanofi SA, ResMed, Teva Pharmaceuticals Industries Ltd, and Vanda Pharmaceuticals. CAC receives royalty payments from Phillips Respironices on sales of the Actiwatch-2 and Actiwatch-Spectrum devices. He has received personal consultancy fees from With Deep Inc and Vanda Pharmaceuticals. CAC received honoraria from Associated Professional Sleep Societies, Massachusetts Medical Society, and the National Sleep Foundation, and travel fees from Stanley Ho Medical Development Foundation and Associated Professional Sleep Societies. CAC has equity interest in Vanda Pharmaceuticals, With Deep Inc, and Signos Inc. CAC is an advisory board member for UK Biotechnology and Biological Sciences Research Council, Institute of Digital Media and Child Development, and Klarman Family Foundation. CAC has received educational or research gifts (to Brigham and Women’s Hospital) from Johnson & Johnson, Mary Ann and Stanley Snider via Combined Jewish Philanthropies, Alexandra Drane, DR Capital Management LLC, Harmony Biosciences LLC, Vanda Pharmaceuticals Inc, Eisai CoLTD, Jazz Pharmaceuticals, Idorsia Pharmaceuticals LTD, Sleep Number Corp, Apnimed Inc, Avadel Pharmaceuticals, Axome Therapeutics Inc, Bryte Foundation, f.lux Software LLC, Stuart F and Diana L Quan Charitable Fund, Casey Feldman Foundation, Roman Catholic Archdiocese of Boston, Summus Inc, Takeda Pharmaceutical Co LTD, Philips Respironics, Abbaszadeh Foundation, Sharon and John Loeb, CDC Foundation, Centers for Disease Control and Prevention, and ResMed Inc. CAC’s interests were reviewed and are managed by the Brigham and Women’s Hospital and Mass General Brigham in accordance with their conflict of interest policies.

  • Not commissioned, not externally peer reviewed.