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Publication Briefs

Protected Sleep Periods for Medical Interns Increase Overnight Sleep and Improve Morning Alertness

A 2009 Institute of Medicine (IOM) report recommended protected sleep periods for medical trainees on extended overnight shifts — a position reinforced by new American Council for Graduate Medical Education (ACGME) requirements. The IOM report recommended a protected sleep period of five hours during any work shift longer than 16 hours to reduce the risk of fatigue-related errors. This study evaluated the feasibility and consequences of protected sleep periods during extended duty. Investigators conducted two randomized controlled trials in parallel: one at the Philadelphia VAMC, and one at the Hospital of the University of Pennsylvania. Between 7/09 and 6/10, 74 interns and 32 senior medical student sub-interns (referred to as interns in this study) were randomized at either the VAMC or University hospital. Twelve 4-week blocks were then randomly assigned to either a standard intern schedule (extended duty overnight shifts of up to 30 hours), or a 5-hour protected sleep period (protected time from 12:30am to 5:30am). Outcome measures were the effect of a protected sleep period on interns' sleep, behavioral alertness, and patient outcomes (e.g., length of stay, transfer to ICU, 30-day readmission rates, and mortality).


  • The implementation of a protected sleep period resulted in approximately a 50% increase in overnight sleep duration, a 200% reduction in nights without any sleep, a reduction of about 50% in disturbed sleep, and improved alertness the next morning.
  • At the VAMC, interns with protected sleep periods had a mean 2.9 hours of sleep vs. 2.0 hours among interns who did not have protected sleep. At the University hospital, interns with protected sleep had a mean of 3.0 hours of sleep vs. 2.0 hours among those without protected sleep.
  • Interns with protected sleep, compared to those without protected sleep, were significantly less likely to have on-call nights with no sleep: 6% vs. 19% at the VAMC, and 6% vs. 14% at the University hospital. Interns with protected sleep also felt less sleepy after on-call nights.
  • The proportion of interns who reported having disturbed sleep at the VAMC was 50% among interns with protected sleep periods compared to 85% among those without protected sleep periods. At the University hospital the equivalent numbers were 53% and 95%.
  • Adherence to the protected sleep period was high; 98% of interns signed out their cell phones as designed.


  • This study was completed before implementation of the 2011 ACGME rules, which no longer allow interns to work shifts longer than 16 hours, and thus findings relate more directly to residents for whom strategic napping is currently recommended.
  • Investigators did not measure other important outcomes (i.e., data entry errors for medications), and because the study was powered based on hours slept, they could not assess small differences in patient outcomes.


  • Protected sleep periods are a viable alternative to 16-hour shifts for interns.
  • Comparative effectiveness studies should examine the impact on patient outcomes of protected sleep periods vs. 16-hour shifts.

PubMed Logo Volpp K, Shea J, Small D, et al. Effect of a Protected Sleep Period on Hours Slept During Extended Overnight In-Hospital Duty Hours among Medical Interns: A Randomized Trial. JAMA December 5, 2012;308(21):2208-17.

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HSR requires notification by HSR-funded investigators about all articles accepted for publication. These journal articles are reviewed by HSR and publication briefs or summaries are written for a select number of articles that are then forwarded to VHA Central Office leadership to keep them informed about important findings or information. Articles to be summarized are selected by HSR based on timeliness of the findings, interest of leadership, or potential impact on the organization. Publication briefs are written for only a small number of HSR published articles. Visit the HSR citations database for a complete listing of HSR articles and presentations.

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