Why a 12-hour shift is unhealthy for nurses

Sleep deficits lead to errors, injuries

The 12-hour shift, mainstay of the nursing schedule, may be unhealthy for nurses and their patients.

That is the conclusion of varied studies that show sleep deprivation and a greater likelihood of drowsy-driving accidents, needlesticks, musculoskeletal injuries, and medical errors. The hazards may be even greater as the nursing workforce ages and becomes more sensitive to sleep deficits, says Jeanne Geiger-Brown, PhD, RN, associate professor and co-director of the Work and Health Research Center at the University of Maryland School of Nursing in Baltimore.

With age, we tend to have less "consolidated" or quality sleep, says Geiger-Brown. Yet we also are less aware of the impact of that sleeplessness, she says. "If you have a young worker who gets sleep deprived they're going to feel it acutely, whereas an older worker will not have that same perception," she says.

Regardless of age, sleep deprivation has consequences. Nurses working shifts of 12.5 hours or longer had three times the risk of medical errors as nurses who worked no more than 8.5 hours, a study at the University of Pennsylvania found.1 A review of studies also found diminished performance and fatigue in nurses who work 12-hour shifts.2

"In general, if a nurse is very sleep deprived, their reaction time and performance is affected," says Alison Trinkoff, ScD, MPH, BSN, RN, FAAN, professor in the University of Maryland School of Nursing.

More than half (51.5%) of hospital staff nurses work 12 or more hours per shift, according to a 2006 analysis that was part of Trinkoff's Nurses Worklife and Health Study.3 About one in five (19%) work more than 12 hours, the study showed. The Institute of Medicine recommends that nurses work no more than 12 hours in a 24-hour period or 60 hours in a seven-day period to avoid fatigue that could lead to errors.4

"We're recommending moving away from [the 12-hour] shift," says Trinkoff. "They just don't seem to be good for nurses or patients."

Paradoxically, one reason that 12-hour shifts persist is because nurses like them. In fact, nurses who don't want to work 12-hour shifts may have already left the hospital setting for other nursing opportunities.

Hospitals can take steps to ensure that schedules allow enough time for rest and minimize fatigue, says Geiger-Brown. Here are some suggestions from the University of Maryland researchers:

Offer shifts of varied lengths: Offering shifts of shorter length can reduce fatigue and may even attract some other nurses back into hospitals, says Geiger-Brown. Older nurses or nurses with young children may even want to work a four-hour shift to help fill in during busy times and provide coverage for nurses who need to take lunch breaks, she says.

"We need shift alternatives besides 12 hours," says Trinkoff. "As nurses get older they may be unable to work long hours. It's extremely taxing work."

Back-to-back 12-hour shifts simply don't provide enough time for sleep, Geiger-Brown says. Nurses who work back-to-back 12-hour shifts generally have only 5.5 hours of sleep, she says.

To allow for more sleep, hospitals could schedule a nurse for an 8-hour shift after she has worked a 12-hour shift, she suggests. "I believe we shouldn't have 12-hour shifts. But if you're going to have them, they should be interspersed with shorter shifts so people can catch up on their sleep."

Use fatigue risk management software: This software uses mathematical algorithms in scheduling to minimize the risk of fatigue. For example, if a nurse wants to work a string of 12-hour shifts in order to have other days off, the scheduling software might show a "red zone" warning that shows the schedule could lead to error-producing fatigue.

When making changes to scheduling policies, it's important to get buy-in from nurses and to work cooperatively with labor unions, says Geiger-Brown. Emphasize the benefits of shorter shifts both to worker health and patient safety, she says.

Screen employees for sleep disorders: Hospitals should screen new hires for sleep disorders, such as sleep apnea, in pre-placement exams, says Geiger-Brown. These can often be successfully treated, she says. Employee health professionals also may want to consider fatigue and sleep disorders when evaluating injuries, she says.

Promote healthy behaviors: Awareness about sleep, shift work, and fatigue is important, says Geiger-Brown. Nurses should take their scheduled breaks during shifts and have access to quiet rooms where they could take a 20-minute nap, if necessary, to maintain alertness.

If a nurse has worked a long shift and feels fatigued, hospitals should offer taxi vouchers for the trips home and back to work, says Geiger-Brown.


1. Rogers AE, Hwang WT, Scott LD, et al. The working hours of hospital staff nurses and patient safety. Health Affairs 2004;23:202-212.

2. Geiger-Brown J, Trinkoff AM. Is it time to pull the plug on 12-hour shifts? Part 1. The evidence. J Nurs Adm 2010;40:100-102.

3. Trinkoff A, Geiger-Brown J, Brady B, et al. How long and how much are nurses now working? AJN 2006;106:60-71.

4. Institute of Medicine. Keeping patients safe: transforming the work environment of nurses. Washington, DC: National Academies Press; 2004.