Napping on the Night Shift: Slacker or Savior?

The American Academy of Sleep Medicine recommends that adults get 7 to 8 hours of nightly sleep² and the National Sleep Foundation (NSF) recommends 7 to 9 hours per night.³ In its 2008 Sleep in America poll,³ however, the NSF found that the average American worker sleeps for only 6 hours and 40 minutes on workday nights, despite long work weeks (54% work 40–49 hours per week, 17% work 50–59 hours, 13% work 60 or more hours weekly) and commuting for 46 minutes each workday. Perhaps even more importantly, 32% of that random sampling of 1000 Americans reported that they “had a good night’s sleep” as infrequently as only a few nights or fewer per month. Because 70% of these average American workers had a marital status of married/partnered, 42% had children at home, and an average age of 47 years, their sleep deficits can manifest in a wide range of subtle to terrifying ways.

Fatigue takes a huge toll on our functional capabilities, leaving us not only physically weary, but cognitively and socially less responsive to people, situations, and events. These consequences of sleep deficits can be categorized as functional, physiologic, neuropsychologic, and safety.

Some of the functional sequelae of sleep deprivation include 29% of Americans reporting that they fell asleep at work in the past month and 12% admitting they were late for work in the last month because of sleepiness.³ 

Some of the highly undesirable physiologic effects of sleep deprivation include the following⁴:

• Heightened appetite and hunger, thought to contribute to obesity

• Diminished respiratory muscle endurance

• Depressed ventilatory responses to hypoxia and hypercapnia

• Impaired immunity marked by increased tumor necrosis factor and interleukin 6

• Possible enhanced risk of cardiovascular disease, insulin resistance, diabetes, and certain cancers

In addition to these systemic changes associated with sleep deprivation, the following quantifiable neuropsychological deficits become apparent, making us more prone to oversights, performance errors, and accidents⁴:

• Significant cumulative, dose-dependent deficits in all cognitive performance tasks

• Erosions in short-term memory and impaired attention

• Diminished motor skills and cognitive information processing

• Changes in mental status that resemble those associated with depression/anxiety

• Diminished reported quality of life

The potential for harm posed by the detrimental effects of extreme fatigue are not infrequently illustrated in reports of fatal car accidents involving drivers who fall asleep at the wheel. The latest NSF Sleep in America poll³ found that among that sample of 1000 workers, 32% admitted that they had driven while drowsy at least once per month during the past year and 2% had experienced an accident or near accident because of driving drowsy.

Health care personnel are not immune to these perils:

• A period of only 20 to 25 hours without sleep diminishes psychomotor performance to a level comparable to someone with a blood alcohol concentration of 0.10%, above the legal limit in many countries.^5 –8 

• Physicians who work 24 hours or longer more than double their risk of being involved in a motor vehicle crash on their drive home compared with those working fewer hours.⁹ 

• The likelihood of being involved in a motor vehicle crash driving home is also greater for physicians coming off a night shift compared with other shifts.¹⁰ 

When the sleep-deprived person is also a health care provider, his or her impaired functioning has the potential to hurt more than work productivity; sleep-deficient health care staff pose harm both to themselves (eg, needlesticks) and to their patients. As the Institute of Medicine’s report¹¹ on medical errors reported nearly a decade ago, a majority of these errors are preventable and some portion are likely attributable to health care staff fatigue precipitating or contributing to adverse outcomes, including the following¹²:

• Administering the wrong drug or drug dosage

• Failure to recognize relevant clinical findings

• Misinterpretations of clinical data

• Mishandling of sharps or other dangerous objects

• Misdiagnosis of patient conditions

• Neglecting to initiate warranted interventions

• Using less than strict infection control practices

Numerous studies have confirmed the relationship between health care staff fatigue and impaired cognitive, psychomotor, and clinical performance.^13,–20 Some of the cumulative effect of this work has been reflected in limitations on the number of hours that medical residents in the United States can work (maximum of 30 consecutive work hours, 80 weekly work hours, and 1 day in 7 must be free of all duties)^21,–22 and recommendations for countering these problems. One of the proposed antidotes for sleep deficits among physicians in training is institution of naps before and during overnight shifts.^23 –24 

The functional, physiological, and recuperative benefits of naps have been anecdotally recognized for centuries and more systematically and scientifically confirmed for decades.²⁵ The National Sleep Foundation identifies the benefits of napping as follows²⁶:

• Restores alertness, directly following the nap and usually for some hours later

• Enhances performance

• Reduces mistakes and accidents

• Affords relaxation and rejuvenation

More than a decade ago, NASA studies on sleepy military pilots and astronauts found that a 40-minute nap improved performance by 34% and alertness by 54% that lasted 2 to 3 hours.²⁷ Even a very short (maximum 6 minutes) period of sleep is effective in enhancing memory.²⁸ Daytime (during the afternoon) naps of less than 30 minutes—even those as brief as 10 minutes—restore wakefulness and promote performance and learning.²⁹ Naps lasting more than 30 minutes, however, appear to be associated with a period of impaired alertness (sleep inertia) immediately after awakening that takes some time to dissipate before wakefulness and performance improve.^26,30 

In order to maximize these beneficial effects and avoid the performance dip associated with longer periods of sleep, many nap advocates prefer the shorter, so-called “power nap.” Before jumping to any premature conclusions regarding the sweet spot for nap duration, however, readers need to be aware that comparably excellent results (fewer performance lapses, less fatigue, less sleepiness, greater vigor, more efficient clinical performance on a simulated venipuncture, and safer performance in a simulated driving test) have been achieved with emergency department physicians and nurses using a nap duration of 40 minutes.³¹ In addition, a recently released study of 23681 healthy Greek men and women between the ages of 20 and 86 found that those who took naps of more than 30 minutes 3 or more times per week had a 37% lower risk of dying from heart disease than those who did not take afternoon naps and those who took naps of any frequency and of any duration demonstrated a 34% lower risk of dying from heart disease.³² 

Since we typically sleep at night, much of the literature related to naps refers to brief periods of sleep that occur during daytime or afternoon hours. So would naps occurring during nighttime hours help those who work at that time? As you may recall from descriptions of circadian cycles, the sprachiasmatic nuclei in the hypothalamus functions as an endogenous circadian pacemaker, driving roughly 24-hour cycles of alertness during the day and sleepiness at night via a myriad of physiological processes including those for body temperature, hormone synthesis, and wakefulness. These rhythms, strongly influenced by natural cycles of daylight and darkness, stimulate release of melatonin from the pineal gland, which lowers alertness and readies the body for sleep. Working the night shift requires considerable effort to overcome these natural circadian cycles, especially when sleeping during the daytime fails to fully compensate for the number of hours of night sleep lost, thereby creating a sleep debt that is cumulative in nature and protracted in duration.^23,24 

For health care staff who work the night shift, naps are effective both before and during the shift^23,24,33:

• a prophylactic afternoon nap (1–2 hours) before the shift starts to take advantage of the natural dip in circadian rhythm and to “bank” sleep against sleep debt, and

• a brief (10–15 minutes) nap during the night shift to maintain alertness, vigilance, and performance and to reduce errors and accidents.

Not exactly. When asked if they ever took a nap at work, nearly 90% of Sleep in America poll respondents said “No.” However, messages about the beneficial effects of napping are being disseminated and heard across the country. The general population, as well as US businesses and health care industry, are listening and beginning to heed those appeals for instituting naps. In the 2008 sleep poll,³ 34% of respondents indicated that their employer allows them to take naps during breaks, although only 24% of workers in public services, safety, or health-related positions and 16% of all workers reported that their employer provided a location to nap. When asked whether they would take naps if their employer allowed it, 26% of those whose employer does not allow it (or those who did not know whether they were allowed to take naps) indicated that they would take naps.

Many big corporate names such as Nike, Ben & Jerry’s Ice Cream, and Deloitte Consulting offer employees the opportunity and some dedicated space to nap, but some of the early pioneers and believers in sleeping on the job have been small, local businesses who viewed their employees as valuable assets. One noteworthy example can be found at Yarde Metals, a metal processing and distribution plant in Connecticut. Craig Yarde, who founded the company in 1976, began using nap rooms around 1997. Shortly thereafter, the Associated Press³⁴ disseminated the early story of this business practice somewhat tongue-in-cheek, but when the New York Times³⁵ followed up 8 years later Mr Yarde reported that his napping program has proven good for morale, productivity, and his workers’ health. Since its launch in Yarde’s basement, the company has expanded to include a new corporate headquarters and multiple buildings in the nearby town of Southington, as well as 7 facilities throughout the East Coast, and international operations. During that growth, the original sofa and easy chairs in the nap room have transformed into a high-tech, computer-controlled Z-lounge, complete with a virtual relaxation system that provides frazzled workers with soothing sounds, vibrations, and visual images of rain forests, waterfalls, and babbling brooks. Perhaps more important than vibrating chairs, however, the business philosophy at Yarde incorporates a management style called Corporate Leveling, which comprises respect and equality, financial transparency, profit-sharing, and “wowing the associates” with lifestyle amenities and some fun.³⁶ It may well be that the naps and high-tech niceties are actually less important than the respect for and investment in his workers these perks and this business philosophy reflect.

So if taking naps at work is already possible at one-third of work sites, it should not be surprising to hear about interest in this practice in our workplace, especially for night shift staff.

At the 2008 annual meeting of the Associated Professional Sleep Societies (APSS), nurse faculty from the University of Manitoba in Winnipeg, Canada, presented a research abstract³⁷ that described the results of a qualitative study they had recently completed with a group of 13 critical care nurses. Researchers used tape-recorded, semistructured interviews with each nurse to gather data related to the experiences, barriers, and napping preferences of night shift critical care nurses. Barriers the nurses identified to being able to take a nap included unstable patients, emergency situations, and staffing shortages. Some nurses reported feeling tired but feared taking a nap. Many nurses who took 20- to 30-minute naps described feeling reenergized, though others felt disoriented. Nurses who were deprived of naps, by contrast, reported severe fatigue, nausea, irritability, diminished alertness, foggy thinking, and less certainty about calculations and decisions, prompting a need to triple check preparations³⁸ and leading to concerns for both the nurse’s health as well as patient safety. The abstract notes that napping strategies need to be developed to assist critical care nurses in combating sleep deprivation.

Planned naps for physicians during the night shift have been reported as early as 1987³³ and other studies involving physicians,³⁹ nurses,⁴⁰ and both nurses and physicians³¹ have reported results comparable to studies examining afternoon naps, that is, that brief naps (10–15 minutes) can improve alertness directly after awakening without the detrimental effects of sleep inertia associated with longer naps.²⁴ 

Both our nursing and medical colleagues enjoin us to consider the benefits of napping on the night shift for the sake of both the health of the health care provider as well as the safety of their patients. I encourage you to do so as well. Although admitting to the possibility of a geographic biasó on this issue, I believe there is more than sufficient evidence to give it some serious consideration. You don’t need to be hasty. Sleep on it awhile. Then revisit the issue refreshed.