Impact of Work Schedules on Sleep Duration of Critical Care Nurses

A. J. Hirsch Allen, MPH; Julie E. Park, MSc; Nassim Adhami, RN; Demetrios Sirounis, MD; Harriet Tholin, RN, BSN; Peter Dodek, MD; Ann E. Rogers, RN, PhD; Najib Ayas, MD, MPH


Am J Crit Care. 2014;23(4):290-295. 

In This Article

Abstract and Introduction


Background. Sleep deprivation leads to reduced vigilance and potentially impairs work performance. Nurses may work long shifts that may contribute to sleep deprivation.

Objective. To assess how nurses' sleep patterns are affected by work schedules and other factors.

Methods. Between October 2009 and June 2010, a total of 20 critical care nurses completed daily sleep and activity logs and a demographic survey and wore an actigraph to objectively measure sleep time for 14 days.

Results. In a multivariate model with controls for repeated measures, mean sleep time between consecutive work shifts was short: 6.79 hours between 2 day shifts and 5.68 hours between 2 night shifts (P = .01). Sleep time was much greater between days when no shifts were worked (8.53 hours), consistent with catch-up sleep during these times. Every minute of 1-way commuting time was associated with a reduction of sleep time by 0.84 minutes.

Conclusion. Critical care nurses obtain reduced amounts of sleep between consecutive work shifts, particularly between consecutive night shifts. Whether this degree of sleep deprivation adversely affects patients' safety needs further study.


Acute and chronic sleep deprivation leads to reduced vigilance, motor discoordination, and impaired cognitive function, thereby increasing the risk of errors in the workplace. Specifically, psychomotor performance after 24 hours of continuous wakefulness is similar to that of persons with a blood alcohol concentration of 0.10%, a level consistent with legal intoxication in many jurisdictions.[1] Increased sleepiness and poorer neurobehavioral performance are associated with less than 5 to 6 hours of time in bed, even for a single night.2 Increasingly, evidence3 indicates that sleep deprivation in health care professionals adversely affects performance and may have adverse effects on patient and occupational safety

Nurses' work shifts in hospitals are usually at least 12 hours long. Frequent work shifts of this length, especially on multiple consecutive days, most likely leave little time for adequate sleep between shifts, especially when time required for commuting and transfer of patient information at shift changes is considered. Additionally, time required for responsibilities at home may further limit opportunities for sleep.[2] Sleep duration may be even less between consecutive night shifts, because the internal biological (circadian) clock reduces sleep drive during the daytime.[4] Although registered nurses are the largest group of health care providers in the United States, the impact of work schedules on sleep patterns of nurses has not been well studied. We think that this topic is an important issue because inadequate sleep duration in nurses could potentially affect their performance and the safety of patients.

The primary purpose of this study was to assess how sleep patterns are affected by work schedules. Specifically, we hypothesized that nurses in the critical care unit obtain inadequate sleep between 2 consecutive work shifts and that this problem would be accentuated between 2 consecutive night shifts. Second, we hypothesized that sleep duration would be reduced by other factors, such as responsibilities at home and commuting time.