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Institute of Medicine (US) Committee on the Work Environment for Nurses and Patient Safety; Page A, editor. Keeping Patients Safe: Transforming the Work Environment of Nurses. Washington (DC): National Academies Press (US); 2004.

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Keeping Patients Safe: Transforming the Work Environment of Nurses.

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Appendix CWork Hour Regulation in Safety-Sensitive Industries1

A substantive body of literature documents the effects of fatigue on worker performance, including the effects of shiftwork and sustained operations on employee alertness. The first section of this appendix reviews this evidence. The second section examines how various health care and non–health care industries have attempted to address consumer and public safety issues by restricting work hours through regulations or administrative guidelines. Since fatigue countermeasures programs are often recommended, a brief overview of these programs and their efficacy is included. Table C-1 at the end of the appendix summarizes hours-of-service regulations in various industries.

TABLE C-1. A Comparison of Work Hour Limitations in Selected Safety-Sensitive Industries.


A Comparison of Work Hour Limitations in Selected Safety-Sensitive Industries.


Fatigue resulting from continuous physical or mental activity is characterized by a diminished capacity to do work and is accompanied by a subjective feeling of tiredness. Fatigue may also result from inadequate rest, sleep loss, or nonstandard work schedules (e.g., working at night). Whatever its origin, fatigue has predictable effects, such as slowed reaction time, lapses of attention to critical details, errors of omission, compromised problem solving (Van-Griever and Meijman, 1987), reduced motivation, and decreased vigor for successful completion of required tasks (Gravenstein et al., 1990). Thus, fatigue causes decreased productivity; tired workers accomplish less, especially if their tasks demand accuracy (Krueger, 1994; Rosa and Colligan, 1988).

Since almost all physiological and behavioral functions are affected by circadian rhythms, the time of day when work occurs is important. Overall capacity for physical work is reduced at night (Cabri et al., 1988; Cohen and Muehl, 1977; Rosa, 2001; Wojtczak-Jaroszowa and Banaszkiewicz, 1974). Reaction times, visual search, perceptual–motor tracking, and short term memory are worse at night than during the daytime (Folkard, 1996; Monk, 1990). On-the-job performance also deteriorates; for example, railroad signal and meter reading errors increase at night, minor errors occur more often in hospitals, and switchboard operators take longer to respond to phone calls (Monk et al., 1996).

The human circadian rhythm strongly favors sleeping during the nighttime hours. Although one study notes that nurses working a permanent night shift or rotating shifts obtained more sleep on average than nurses working day or evening shifts, almost one-fifth of the nurses reported having struggled to stay awake while taking care of a patient at least once during the previous month (Lee, 1992). Another study found that falling asleep during the night shift occurred at least once a week among 35.3 percent of nurses who rotated shifts, 32.4 percent of nurses who worked nights, and 20.7 percent of day/evening shift nurses who worked occasional nights (Gold et al., 1992). It was also found that nurses working night or rotating shifts made more on-the-job procedural errors and medication errors because of sleepiness than nurses working other shifts. Sleepiness appeared to be confined to the night shift, as none of the shift rotaters or day/ evening nurses who worked occasional nights reported significant difficulties remaining alert on other shifts.

These subjective reports of sleeping on duty were recently verified by both activity (wrist actigraphy) and sleep (polysomnographic) recordings of 15 French nurses who worked at night (Delafosse et al., 2000). Only 4 of the 15 nurses were able to remain awake all night at work; the others averaged 86.5 (standard deviation [SD] ± 77.6) minutes of sleep while on duty.

Moreover, difficulties maintaining alertness at night are not confined to nurses; episodes of both subjective (or self-reported) and objective sleep were recorded while U.S. Air Force traffic controllers were on duty at night (Luna et al., 1997), and episodes of drowsiness at the wheel were observed in the majority of 80 commercial truck drivers (Wylie et al., 1996).

A person who is not sleep deprived performs tasks more efficiently after prolonged wakefulness and can cope better with nonstandard work hours (nights or rotating shifts) than someone with a sleep deficit (Dinges et al., 1996). Individuals working nights and rotating shifts rarely obtain optimal amounts of quality sleep. Their sleep is shorter, lighter, more fragmented, and less restorative than sleep at night (Knauth et al., 1980; Lavie et al., 1989; Walsh et al., 1981).

Workers are more likely to report greater fatigue at the end of 12-hour work shifts than at the end of 8-hour workshifts (Mills et al., 1983; Rosa 1995; Ugrovics and Wright, 1990). There are exceptions, however: mineworkers reported no differences in fatigue after 8- and 12-hour shifts despite high physical workloads (Duchon et al., 1994), and computer operators reported reduced tiredness throughout the shift after switching from 8-hour to 12-hour shifts (Williamson et al., 1994). Although the timing and duration of meal breaks and “coffee” breaks were not described in these studies, in the case of unionized mineworkers, it is likely they were allowed to stop working for brief periods during their work shift.

Sustained operations (shifts of 12 or more hours with limited opportunity for rest and no opportunity for sleep) (Krueger, 1989) often occur among health care providers who staff busy emergency rooms and intensive care units (ICUs), work overtime shifts on nursing units, or work as members of surgical teams that perform lengthy or consecutive procedures (Krueger, 1989). The majority of anesthesiologists and anesthesia residents report having made errors in the administration of anesthesia when fatigued (Gravenstein et al., 1990). The California Nurses Association (CNA) website (CNA, 2001a) reports several serious errors committed by nurses mandated to work 16-hour shifts, in addition to cases in which nurses did not make errors but were at high risk for doing so. For example, a nurse who worked on average one mandatory double shift (16 hours) every 2 weeks for a 2-month period reported that “by 4 a.m. I was so exhausted that I would stop between going from one baby to the next and completely forget why I was going to the other bedside. Another time, again about 4 a.m., I would sometimes stop in the middle of the floor and forget what I was doing.”

Studies have shown that accident rates increase during overtime hours (Kogi, 1991; Schuster, 1985), with rates rising after 9 hours, doubling after 12 consecutive hours (Hanecke et al., 1998), and tripling by 16 consecutive hours of work (Akerstedt, 1994). Data from aircraft accident investigations of the National Transportation Safety Board (NTSB) also show higher rates of error after 12 hours (NTSB, 1994a). Finally, night shifts longer than 12 hours and day shifts longer than 16 hours have consistently been found to be associated with reduced productivity and more accidents (Rosa, 1995).

Laboratory studies have shown that moderate levels of prolonged wakefulness can produce performance impairments equivalent to or greater than levels of intoxication deemed unacceptable for driving, working, and/or operating dangerous equipment (Dawson and Reid, 1997; Lamond and Dawson, 1998). In one study, performance on neurobehavioral tests remained relatively stable during the first 17 hours of testing, a period the researchers called the normal working day, then decreased linearly, with the poorest performance occurring after 25–27 hours of wakefulness (Lamond and Dawson, 1998). Performance on the most complex task—grammatical reasoning—was impaired several hours before performance on vigilance accuracy and response latency (20.3 versus 22.3 and 24.9 hours, respectively). Although Dawson and colleagues (Dawson and Reid, 1997; Lamond and Dawson, 1998) were the first to report that prolonged periods of wakefulness (i.e., 20–25 hours without sleep) can produce performance decrements equivalent to a blood alcohol concentration (BAC) of 0.10 percent, numerous other studies have shown that prolonged wakefulness significantly impairs speed and accuracy, hand–eye coordination, decision making, and memory (Babkoff et al., 1988; Florica et al., 1968; Gillberg et al., 1994; Linde and Bergstrom, 1992; Mullaney et al., 1983).

The combination of sustained wakefulness and working at night is particularly hazardous (Gold et al., 1992; Smith et al., 1994). When the Exxon Valdez ran aground around midnight on March 23, 1989, the third mate had been awake 18 hours and anticipated working several more hours (Alaska Oil Spill Commission, 2001). Although the explosion of the Challenger space shuttle occurred during the daytime, the decisions made the night before the launch by mission control staff have been cited as a major factor contributing to the explosion (Mitler et al., 1988).

The lack of adequate rest periods between workshifts can also exacerbate fatigue. Sleep loss is likely to occur when there are only short durations between work shifts. Most adults require at least 6–8 hours sleep to function adequately at work (Krueger, 1994). The loss of even 2 hours of sleep affects waking performance and alertness the next day (Dinges et al., 1996). After 5 to 10 days of shortened sleep periods, the sleep debt (sleep loss) is significant enough to impair decision making, initiative, information integration, planning, and plan execution (Krueger, 1994). The effects of sleep loss are insidious and until severe, usually are not recognized by the sleep-deprived individual (Dinges et al., 1996; Rosekind et al., 1999).

Very short off-duty periods (i.e., 8 hours or less) do not allow for commuting time, recovery sleep, or time to take care of domestic responsibilities (Dinges et al., 1996; Rosa, 1995, 2001). Off-duty intervals ranging from 10 to 16 hours are either suggested or already mandated for many transportation workers (Dinges et al., 1996; Gander et al., 1991b; Mitler et al., 1997). No amount of training, motivation, or professionalism will allow a person to overcome the performance deficits associated with fatigue, sleep loss, and the sleepiness associated with circadian variations in alertness (Dinges et al., 1996; Rosekind et al., 1995). Nor will training, motivation, or professionalism reduce the greater crash risk and increased drowsiness or sleepiness reported by commercial truckers after fewer than 9 hours off duty (McCartt et al., 2000). Recovery from extended work periods requires several days; schedules that require workers to return to work after an 8-hour rest period or to transition from night to day or evening shifts without at least 24 hours off are considered particularly dangerous (Olson and Ambrogetti, 1998; Rosa and Colligan, 1988).

Fatigue is also exacerbated by increased numbers of shifts worked without a day off (Dirkx, 1993; Knauth, 1993), and working more than four consecutive 12-hour shifts is associated with excessive fatigue and longer recovery times (Wallace and Greenwood, 1995). However, two consecutive nights of recovery sleep can return performance and alertness to normal levels, even following two or three 12-hour shifts (Dinges et al., 1996; Tucker et al., 1996), and longer intervals between works days are even more beneficial. Workers obtain more sleep and start their next shifts with less fatigue. The first or second night in a new series of night shifts, however, may be the most fatiguing because of circadian desynchrony (Rosa, 2001).

Predictability of work schedules assists in planning ahead for rest periods. Gold and colleagues (1992) found that nurses who worked rotating shifts reported more accidents than those who were day/evening rotaters. Unscheduled overtime, especially when added to a scheduled work shift, may require 16–20 hours of consecutive work for health care providers and those working in other professions (Rosa, 2001).


The work schedules of both physicians and nurses, as outlined later in this appendix, are often quite demanding. Although the work hours of truck drivers, locomotive engineers, and pilots are regulated to protect the public from fatigue-related errors, hospitalized patients lack similar protections. At present, there are no restrictions on the number of hours a nurse may voluntarily work in a 24-hour or a 7-day period in the United States. Nor are there restrictions on the number of hours that may be worked by other hospital employees, such as pharmacists (another profession with a developing shortage), and only minimal restrictions exist on hours worked by physicians.


The hours worked by registered nurses (RNs) are of particular concern since they provide the bulk of direct inpatient hospital care; moreover, studies have demonstrated that the care provided by RNs is vital for maintaining the well-being of hospitalized patients (Aiken et al., 2002; Kovner and Jones, 2002; Needleman et al., 2001). RNs must be alert enough to provide safe care for their patients and to recognize potentially dangerous errors in medication orders. Most previous studies evaluating medical errors took place in environments where nurses had obtained adequate amounts of sleep and were not unduly stressed by workloads, subjected to understaffing, or fatigued from working overtime (Cullen et al., 1997). Today, however, hospital nurses report extremely stressful working conditions, increased numbers of acutely ill patients, inadequate staffing, and working long hours without breaks (Murray and Smith, 1988; Schrader, 2000; Seccombe and Smith, 1996). The effects of these working conditions on patient safety are unknown, but may be significant since a large number of medication errors reported in one study were attributed to poor staffing and onerous work schedules (Leape et al., 1995).

Scheduled shifts may be 8, 10, or 12 hours, and may not follow the traditional pattern of day, evening, or night shifts. Although 12-hour shifts usually start at 7 p.m. and end at 7 a.m., some start at 3 a.m. and end at 3 p.m. Nurses working on specialized units, such as the operating room, dialysis units, and some ICUs may be required to be “on call” in addition to their regularly scheduled shifts. Shifts lasting 24 hours are becoming more common, particularly in emergency rooms (ERs) and on units where the nurses self-schedule (personal communications, ER nurse, June 2002, and ICU nurse, September 2002, University of Pennsylvania Hospital).

Maintaining adequate staffing levels is a difficult problem, especially during nursing shortages. Hospitals can hire contract staff for specific periods to cover vacant positions or to cope with seasonal fluctuations in demand. Agency nurses, who are not employees of the hospital, can also be used. The use of agency nurses, however, is very expensive, and the quality of care provided by these nurses has been questioned (Brusco et al., 1993). Asking regular nursing staff to work extra hours is often attractive to administrators since it costs less than hiring agency nurses, and the nurses are already familiar with the hospital (Brusco et al., 1993). Furthermore, unless specified in collective bargaining agreements, there are no federal (and only a few state) regulations restricting the number of hours a nurse can work in a 24-hour period or over a period of 7 days.

To maintain adequate staffing levels, hospitals frequently offer nurses significant incentives to work extra hours. For example, nurses at the University of Pennsylvania Hospitals are paid time and a half plus an extra $25.00 per hour for working overtime (personal communication, October 2002), while nurses in the University of California system are paid double time (CNA, 2001b). Likewise, nurses at the University of Michigan Medical Center recently approved a contract that requires the hospital to pay 2.5 times their normal wage when they volunteer for overtime in advance (CNA, 2001b). Everyone appears to benefit. When the incentives are high enough, hospital administrators can cover open shifts without hiring additional staff, agency nurses, or traveling nurses, and nurses can significantly increase their salaries by working extra hours or shifts. The effects on patient care, however, are unknown.

The use of overtime, whether mandatory or voluntary, to cope with staffing shortages is quite common in hospital and nursing home settings. Interviews with staff members who worked at 17 nursing homes studied by Louwe and Kramer (2001) revealed that in 13 of the 17 facilities, at least one nursing staff member, and usually more, had worked between one and three double (16-hour) shifts during the previous 7 days. In 5 of the facilities, at least one staff member had worked four to seven double shifts in the last seven days. And in one facility, more than one-third of the nursing staff had worked between eight and eleven double shifts in the past 14 days. Although all direct-care nursing staff (RNs, licensed practical nurses [LPNs]/ licensed vocational nurses [LVNs] and nursing assistants) worked extra hours, the majority of double shifts were worked by nursing assistants.

Anecdotal evidence suggests that hospital nurses are also working large amounts of overtime because of short staffing. Nurses continue to report working over 13 hours with only a 20-minute break (Northcott, 1995), and working “four eight hour shifts in two days—32 hours during a 40-hour stretch, leaving the hospital only once for an eight-hour break” (CNA, 2001a). A recent poll conducted by the American Association of Critical Care Nurses (AACCN) indicated that the use of mandatory overtime is also quite common in the United States (AACCN, 2001). Only 40 percent of 2,125 respondents had never been required to work mandatory overtime. Approximately one-third (31 percent) reported working mandatory overtime at least once a month, another 22 percent at least once every 2 weeks, and 7 percent (n = 149) at least once a week. Another poll conducted by the American Nurses Association showed similar results: approximately 60 percent of respondents (n = 4,258) reported being forced to work voluntary overtime (ANA, 2001).

Decisions about mandatory overtime are usually made at the last minute, and nurses may receive less than 60 minutes' notice that they will not be allowed to go home at the end of their scheduled shift (author's unpublished data). No special accommodations are made for nurses working an extra shift; they are simply assigned a group of patients and expected to provide high-quality care with no additional breaks or a chance to take a short nap between shifts (author's unpublished data). This practice is particularly dangerous when nurses are required to work extra hours at night. Under such conditions, the nurse may have been awake up to 24 hours, working 16 of those hours and often having only a 30- or 60-minute break.

The potential dangers posed by such overtime hours have been clearly documented. For example, the extensive use of overtime has been identified as a contributor to two separate outbreaks of Staphylococcus aureus (Arnow et al., 1982; Russell, et al., 1983). At the time, both hospitals were contending with an unexpected increase in patient census, coupled with understaffing. Investigations showed that the nurses, who were fatigued and stressed, compromised the usual standards of care by skipping steps or rushing through aseptic procedures.

Legislation has been introduced at both the federal and state levels to ban mandatory overtime. Two bills were introduced during the 107th U.S. Congress that would prohibit mandatory overtime for nurses and other licensed health care providers (Golden and Jorgensen, 2002). The first bill2 would amend Title XVIII of the Social Security Act (Medicare Act), while the second bill3 would amend the Fair Labor Standards Act. The Safe Nursing and Patient Care Act of 2001 also contained provisions that would have required the Agency for Healthcare Research and Quality to conduct a study to determine the numbers of hours a nurse can work without compromising the safety of patients. Similar legislation has been introduced in the 108th Congress.

State legislatures in approximately 19 states have considered bans on mandatory overtime for nurses and other health care professionals. Most proposed measures prohibit hospitals from requiring nurses to work more than their regularly scheduled 8- or 12-hour shifts. Some bills specify that nurses cannot be required to work more than 40 hours a week, while others prohibit hospitals from requiring employees to work more than 80 hours of overtime in any consecutive 2-week period (Golden and Jorgensen, 2002). Maine's law (Ch. 401) also mandates that if nurses work longer than 12 hours, they must be given at least 10 hours off before their next shift (Golden and Jorgensen, 2002). To date, bills prohibiting mandatory overtime for nurses have passed in only four states—California, Maine, New Jersey, and Oregon. No measure, either proposed or enacted, addresses how long nurses may work on a voluntary basis.


The hours physicians work, particularly during their residency training, are often quite demanding. Although the Association of American Medical Colleges (AAMC) and the Accreditation Council for Graduate Medical Education (ACGME) have recommended that house staff work no more than 80–84 hours per week, it is still common for medical residents to work over 100 hours per week for prolonged periods (Patton et al., 2001). Work days are typically 12–14 hours (Czeisler et al., 2002), and workloads vary by specialty (Patton et al., 2001), with surgical residents typically working the longest hours (Committee of Interns and Residents, 2002a; Owens et al., 2001; Silberger et al., 1988). Despite recommendations that work shifts not exceed 24 consecutive hours, many interns and residents remain subject to call schedules requiring duty periods of up to 36 consecutive hours or longer on weekends (Czeisler et al., 2002; Leonard et al., 1998; Owens et al., 2001). Other residents opt to work 60–84 consecutive hours (Friday or Saturday morning through Monday afternoon) in a single “power weekend” each month (Czeisler et al., 2002).

The work hours of resident physicians have been the subject of research and frequent debate over the past 20–25 years. Although errors made by a sleep-deprived resident in a New York City hospital are believed to have caused a patient's death, few studies have shown a direct link between fatigue and patient safety (Asken and Raham, 1983; Friedman et al., 1971; Parker, 1987; Poulton et al., 1978). The findings of Smith-Coggins and colleagues are typical. Emergency room physicians working at night reported feeling significantly more sluggish, less motivated, and less clear-thinking than when working days. Although, they were able to maintain their accuracy in interpreting 12-lead electrocardiograms (ECGs) and rhythm strips, their reactions times were slower and they took longer to intubate a mannequin when working the night shift (Smith-Coggins et al., 1997).

Only a few studies have demonstrated that clinical performance is adversely affected by sleep deprivation. Unlike earlier studies, recent studies have been tightly controlled. Earlier methodological flaws (e.g., tests that were too short or tested factual knowledge, which is relatively insensitive to sleep deprivation; included performance incentives; or, most significantly, failed to control for the residents' actual sleep schedules prior to and during the studies) (Weigner and Ancoli-Israel, 2002) have been corrected. Researchers no longer expect to find differences between “rested” residents—e.g., those who had more than 4 hours of sleep (Bartle et al., 1988; Deaconson et al., 1988; Light et al., 1989), more than 5 hours of sleep, (Hawkins et al., 1985; Reznick and Folse, 1985), or “regular” sleep (Denisco et al., 1987; Storer et al., 1989), or were not on call (Orton and Gruzelier, 1989)—and “fatigued” residents. They assume all residents have a significant sleep deficit, even those tested when not on call (Weigner and Ancoli-Israel, 2002).

Several studies have shown impaired performance on measures of alertness and concentration, standardized tests of creative thought processes, and cognitive performance on a standardized computerized test battery after on-call periods ranging from 24 hours to an entire weekend (Leonard et al., 1998; Nelson et al., 1995; Wesnes et al., 1997). In studies using virtual-reality simulations, surgical residents made more errors and were slower to complete electrocoagulation of bleeding tissue as sleep loss increased (Taffinder et al., 1998). Moreover, error rates were higher among residents after a night on call than during normal daytime hours (Grantcharov et al., 2001). Realistic patient simulators have also been used to evaluate the performance of anesthesiologists at night when fatigued and during regular workdays (Ou et al., 2001), as well as under conditions of acute sleep deprivation (e.g., awake for 25 hours) or being well rested (2 hours of extra sleep on average for four consecutive nights before the study) (Gaba, 1998; Weigner et al., 1998). Videotapes from the latter study showed sleep-deprived residents actually falling asleep while administering anesthesia.

Despite evidence that patient care may be compromised if a fatigued, sleep-deprived clinician is allowed to operate, administer anesthesia, manage a medical crisis, or deal with an unusual or cognitively demanding clinical presentation (Weigner and Ancoli-Israel, 2002), there is significant resistance to limiting the hours worked by resident physicians. Concerns have been expressed about reduced learning opportunities if resident work hours are curtailed (Greenfield, 2001; Holzman and Barnett, 2000; Suk, 2001), as well as decreased professionalism and commitment to patients (Holzman and Barnett, 2000). Current resident work hours have also been defended on economic grounds (Green, 1995; Patton et al., 2001; Thorpe 1990).

Only the state of New York limits the hours worked by resident physicians. The “Bell Regulations”4 were enacted following the death of Libby Zion, the 18-year old daughter of Sidney Zion, an attorney and writer for the New York Times, in 1984. Her death triggered an aggressive media campaign questioning the quality of care in teaching hospitals, as well as a grand jury investigation into her death (Asch and Parker, 1988; Kwan and Levy, 2002). Although neither the hospital nor physicians were faulted, the grand jury did find fault with the residency training system and physician staffing patterns that allowed Libby Zion's death to occur. Five specific factors were identified as contributing to her death: (1) she was not examined by an attending physician with experience in emergency medicine when admitted to the ER in an agitated condition, complaining of fever; (2) after transfer to a medical unit, she was cared for by first- and second-year residents who were largely unsupervised; (3) she was admitted at 2:00 a.m., when both residents caring for her had been at work for 18 straight hours; (4) the first-year resident ordered that she be placed in physical restraints without reevaluating her condition; and (5) she was given meperidine (Demerol) despite the resident's knowledge that she was also taking phenalzine.5

In March 1987, the New York State Commissioner of Health appointed an Ad Hoc Advisory Committee on Emergency Services to analyze the grand jury's findings. The committee, chaired by Dr. Bertand Bell, reviewed the grand jury's report and issued several recommendations to the New York State Department of Health, including that residents should not work more than 80 hours per week, more than 24 consecutive hours, or more than 6 days without at least one 24-hour period off duty (Holzman and Barnett, 2000; Kwan and Levy, 2002). Rest periods of at least 8 hours between shifts were also mandated (Holzman and Barnett, 2000). ER residents and attending physicians were limited to 12-hour shifts (Kwan and Levy, 2002). The committee's recommendations were then incorporated into the New York State Code in 1989. Although the New York Hospital Association immediately filed suit contending that the regulations were arbitrary, had been improperly adopted, and failed to provide adequate reimbursement for the increased costs of their implementation,6 its appeal to the State Supreme Court failed (Patton et al., 2001).

Also in 1989, the ACGME amended its regulations to require accredited internal medicine residency programs to limit the hours worked by residents. Internal medicine residents could spend no more than 80 hours per week providing patient care, could be on call no more than every third night, and on average would have to have the opportunity to spend at least 1 of every 7 days free of patient care duties (Green, 1995). Today there are 26 sets of different guidelines, each developed by a different Residency Review Committee. Weekly work hour limitations range from “whatever is considered ‘appropriate' by residency directors” (general surgery) to 72 hours (emergency medicine) (Gurjala et al., 2001; Kwan and Levy, 2002). Not only are the guidelines inconsistent across the various specialties, but they are also voluntary, not mandatory.

Neither the Bell Regulations in New York nor the ACGME guidelines have been effective in curtailing the hours worked by resident physicians (Gurjala et al., 2001; Kwan and Levy, 2002). Fully 92 percent of New York hospitals were not complying with the Bell Regulations during 1991–1992, a fact known by the New York State Department of Health (Patton et al., 2001). In a survey conducted almost 10 years after the Bell Regulations were enacted, residents in all New York teaching hospitals reported working an average of 95 hours per week (Anonymous, 1998). In 1998, a surprise investigation conducted by the New York State Department of Health found all 12 hospitals visited to be violating resident work hour limits. Over one-third of the residents (38 percent) had worked in excess of 24 consecutive hours, 37 percent were working more than 85 hours per week, and 20 percent had exceeded 95 hours per week, while 60 percent of surgical residents had exceeded 95 hours per week (Kennedy, 1998). Despite increased fines and stepped-up enforcement efforts, some residency programs in New York continue to violate daily and weekly work hour limitations (Committee of Interns and Residents, 2002b).

All residency programs in the United States undergo periodic accreditation reviews by the ACGME. Although none have lost their accreditation solely for overworking residents (Kwan and Levy, 2002), 20 percent of the residency programs reviewed in 1999 were cited for noncompliance with work hour standards (Kwan and Levy, 2002). In 2000, only 8 percent of the programs reviewed that year were cited (Lamberg, 2002).

During the past year, increasing attention has been paid to hours worked by resident physicians. The ACGME has recommended that all residency programs limit resident work hours to 80 hours/week and have a maximum shift length of 24 hours (although a resident could be required to put in an additional 6 hours for transfer of patient care responsibilities, educational debriefing, didactic activities, and seeing patients in a post-call continuity clinic), and that night call be limited to every third night. Recommendations from the American Medical Association (AMA) and the AAMC are quite similar, and stress a voluntary approach (AMA, 2002; AAMC, 2002). A petition submitted in spring 2002 to the Occupational Health and Safety Administration (OSHA) by Public Citizen and the American Medical Student Association called for federal regulation, civil penalties, and public disclosure of violating hospitals (Gurjala et al., 2001). OSHA denied the petition on October 10, 2002, citing the voluntary standards being adopted by the ACGME (Public Citizen, 2002).

As discussed earlier, legislation to amend title XVIII of the Social Security Act (Medicare Act) was introduced in both houses of the U.S. Congress during the 107th session. The Patient and Physician Safety Act of 20017 would have required any hospital receiving Medicare funding to limit the hours worked by postgraduate trainees to no more than 80 hours per week and 24 hours per shift. H.R. 3236 was introduced on November 6, 2001, and referred from the House Energy and Commerce Committee to the House Subcommittee on Health on March 5, 2002.8 The Senate version of the bill (S. 2614) was introduced June 12, 2002, and immediately referred to the Senate Committee on Finance.9 No further action was taken.

In June 2001, legislation was introduced and passed by the New Jersey State Assembly limiting the work hours of resident physicians in that state to an average of 80 hours/week over a 4-week period and 24 consecutive hours of duty (A. No. 1852) (Committee of Interns and Residents, 2002b). If the bill is passed by the state senate and approved by the governor, on-call duties during night shifts will also be limited to no more than every third night, and hospitals will not be able to require residents to work more than 6 days per week.


Police and Firefighters

Although the services of police officers and firefighters are required 24 hours a day, 7 days a week, their typical work schedules are quite different. Firefighters in many jurisdictions work for 24-hour periods followed by 48 hours off, whereas police officers are often subjected to rotating shifts, must put in extra hours to appear in court and/or complete paperwork, and may moonlight to supplement their income. Only limited research is available about the effects of fatigue in these two occupational groups.

Although overwhelming fatigue was described by police officers testifying at hearings conducted by the National Commission on Sleep Disorders Research in 1991 (DHHS, 1993), it was not known whether the witnesses' experiences were representative of the larger population of police officers. Over the past 10 years, newspaper reports of automobile accidents due to police officers falling asleep and running red lights, running off the road and hitting trees or joggers, or crashing while chasing fleeing motorists have provided anecdotal evidence that at least some police officers have significant problems with fatigue (Vila and Kenney, 2002). Results of a recent study of four medium-sized metropolitan police departments suggest that 6 percent of officers on duty at any one time are severely impaired by fatigue, and that nearly half have clinical sleep pathologies (Vila, 1996). Fewer than 26 percent of the participating officers reported averaging 7 hours of sleep a day, and nearly 12 percent obtained less than 5 hours per day. Nearly 16 percent reported trouble staying awake during normal activities such as driving, eating meals, or engaging in social activities.

There are no regulations limiting the number of hours worked by police officers. Surveys have shown that at least a few officers in most departments work substantial overtime, and that more than half of the officers in many departments moonlight (Vila and Kenney, 2002). Mean overtime hours range from 17.5 to 100 per month.

Several studies suggest that lengthening work shifts and decreasing the number of days worked per week may reduce fatigue among police officers. Officers working 10- and 12-hour days reported that the longer shifts were less fatiguing. They also reported fewer sleep problems and significantly less fatigue at the beginning of their shifts (Vila and Kenney, 2002). Switching to a compressed work week (three 13.5-hour shifts followed by four days off) also improved productivity in Bexar County, Texas, and did not lead to greater fatigue or increased moonlighting (Vega and Gilbert, 1997). Finally, changing the direction of shift rotation (from backward to forward), speeding up the rate of shift rotation, lengthening the shift to 8.5 hours, and reducing the number of consecutive shifts to four resulted in a four-fold decrease in the numbers of Philadelphia police officers reporting poor sleep, twice as many reporting no daytime fatigue, a decrease in sleep episodes on duty, a decline in the number of on-the-job motor vehicle accidents per mile driven, an increase in alertness on night shifts, and a reduction in the use of sleeping pills and alcohol (Center for Design of Industrial Schedules, 1988).

Agencies are being encouraged to review their policies and procedures related to shift scheduling, moonlighting, and number of consecutive days worked and to provide in-service training on the importance of adequate sleep, the hazards associated with shift work, and strategies for managing those hazards (Vila, 1996, 2000). Information is scarce on whether these recommendations are being adopted and if so, how effective they are.

Firefighters typically work approximately 9 to 10 days per month and average 52–56 hours on duty per week (Anonymous 2002 a,b). Although they are on duty for longer periods than most people, not all hours spent at the firehouse are devoted to working; part of the time is devoted to meal preparation, housekeeping chores, recreational activities, and sleep.

Military Personnel

Although the U.S. military has few regulations or guidelines regarding hours of service or duty restrictions, all branches are acutely aware of the adverse effects of fatigue on performance. During normal conditions at post, camp, and duty stations where personnel can go home at night, work hours are quite similar to those of civilians. When personnel are deployed in the field or at sea, they tend to work about 70 hours per week (U.S. Congress Office of Technology Assessment, 1991c).

Combat operations impose unique demands. Work demands are often continuous, requiring individuals to maintain performance for 12 hours or more. Sleep may be difficult or impossible. Nighttime operations, jet lag due to rapid aerial deployments, extra tasks associated with the first day or two at sea, and a faster-than-usual tempo of operations can further limit endurance (U.S. Congress Office of Technology Assessment, 1991c).

Tasks requiring physical activity and effort (e.g., infantry marches, handling supplies, and preparing fortifications) are affected less than other tasks by time of day, moderate sleep loss, or other circadian disruptions (Belenky et al., 1987; Haslam, 1982; Ryman et al., 1987). Several days of sustained operations will degrade the vigilance, memory, and cognitive task performance of infantry soldiers, tank crews, and artillery fire direction teams (Krueger, 1989), while performance on tasks requiring constant vigilance (e.g., sonar operations) can degrade within less than an hour (Krueger, 1989; Poulton, 1972).

Long flights and sustained operations involving aircraft can be quite hazardous. Fighter pilots can maintain physical coordination despite extreme sleepiness (Krueger et al., 1985), but judgment and planning abilities are extremely sensitive to the onset of fatigue (Graeber et al., 1986; Kopstein et al., 1985; Word, 1987). Although not studied, the performance of other tasks, such as maintenance, preparation, and operation of equipment (e.g., weapon systems, communication systems, and construction equipment), is also likely to be affected by fatigue and time of day (U.S. Congress Office of Technology Assessment, 1991c).

The Army, Air Force, and Navy have regulations governing flight times and duty periods for pilots. The Army specifies both the maximum amount of time pilots are allowed to fly and their maximum duty periods. Flight times are adjusted for such factors as time of day (flying 1.0 hour at night is considered the same as flying 1.4 hours during the day), instrument conditions, and whether the pilot is required to wear night vision devices or protective gear (U.S. Congress Office of Technology Assessment, 1991c). Flight times for Air Force pilots are longer (up to 12 hours in duration for a single crew). Total flying time is limited to 75 hours per 30-day period and 200 hours per 90 consecutive days. A minimum rest period of 12 hours is mandated between flights and must include 8 hours of uninterrupted, continuous rest. If a crew member is interrupted and cannot get 8 hours of rest, he or she must be given 8 more hours of uninterrupted time for rest, plus additional time for other activities. Flight surgeons and aviation safety officers are usually involved in scheduling missions. However, the commanding officer can waive the regulations for high-priority missions and in combat situations.

Naval regulations are quite similar, but specify that pilots cannot be assigned to flight duty on more than 6 consecutive days or assigned continuous alert or flight duty for more than 18 hours. If the 18-hour rule is exceeded, 15 hours of continuous off duty time must be given to the crewmember. Any deviation from this protocol requires that the individual be closely monitored and cleared for each flight by the commanding officer in consultation with the flight surgeon (U.S. Congress Office of Technology Assessment, 1991c).

Flight surgeons also have the authority to issue stimulants and hypnotic medications to pilots to facilitate sleep and maintain alertness during combat conditions. Crewmembers are encouraged to defer non–flying-related duties in the days before a mission, take short frequent naps, consume nutritious meals, and use caffeine judiciously (Naval Strike and Air Warfare Center, 2000). If a long flight or compromised alertness during a flight is anticipated, pilots may be issued several tablets of amphetamine (5 mg) at the beginning of the flight. No one is required to take amphetamines, and any leftover doses are collected at the end of the flight. Hypnotics are never issued prior to a flight to prevent their inadvertent use in place of a stimulant.

The use of medications to promote sleep and/or alertness among pilots is not new. According to Performance Maintenance during Continuous Flight: A Guide for Flight Surgeons (Naval Strike and Air Warfare Center, 2000), both British and German pilots used amphetamines during World War II. British pilots used sedatives during the Falklands conflict, and both Air Force and Navy pilots were given amphetamines in Viet Nam and most recently during Desert Storm. Flights during Desert Storm often exceeded the legal durations, sometimes lasting up to 15–18 hours. Amphetamine use was most common in the early morning hours or just after dawn during extended combat air patrol missions.

Although there are no specific guidelines for work and duty schedules for most Army activities and operations, commanding officers are responsible for ensuring that personnel under their command are rested and fit for duty. Commanders are encouraged to plan for at least 6 hours of rest for combat personnel (those doing the fighting) (U.S. Congress Office of Technology Assessment, 1991c). However, actual conditions dictate the nature and scheduling of rest periods during combat conditions, reinforcement operations, and special operations.

The Air Force has maximum duty limits for all personnel (e.g., flight and nonflight) that apply even during combat. Staff can work 10 hours a day, 6 days a week, for a total of 247 hours a month during continuous operations, and up to 12 hours a day, 6 days a week, for a maximum of 30 days during sustained operations (U.S. Congress Office of Technology Assessment, 1991c). Crews manning intercontinental ballistic missile silos are on alert duty for 24-hour periods. Regulations require that all crewmembers have at least 6 hours for rest or sleep during their duty period. Crews are rotated and tend to be on duty every third day (U.S. Congress Office of Technology Assessment, 1991c).

At-sea schedules for nonflight naval personnel can be quite rigorous. Workweeks of 70–80 hours are not uncommon. Even under noncombat conditions, rotating watch schedules can cause significant circadian disruption (U.S. Congress Office of Technology Assessment, 1991c). Submarine crews typically use 18-hour watch schedules involving three sections of personnel rotating 6 hours on and 12 hours off. Because of maintenance tasks and administrative and training requirements, crewmembers sleep on average only 4 hours out of every 18-hour period (U.S. Congress Office of Technology Assessment, 1991c). Although 12-hour watch schedules are typical, this does not imply that personnel on surface ships have 12 consecutive hours off duty. Instead, crewmembers usually work for 6 hours, then have 6 hours off for other tasks, including sleeping and eating. During normal conditions, crewmembers average about 6 hours of sleep in 24 hours (U.S. Congress Office of Technology Assessment, 1991c). Although crews manning aircraft carriers usually do not follow a rotating watch schedule as do crews on other surface ships, they usually work for somewhat longer periods (14–16 hours). Combat conditions, which require the entire crew of a ship to remain on duty without relief or rest periods, can induce significant acute fatigue, especially after 1 or 2 days.

Many Marine Corps missions are planned to begin before dawn, when the enemy is believed to be less vigilant and effective. There is generally a very intense period of sustained operations, usually the first 36–48 hours, after an amphibious assault, when personnel are almost continuously active (U.S. Congress Office of Technology Assessment, 1991c). Marine air forces, which provide air support for amphibious assaults and other ground operations, are normally governed by the same flight regulations as other Navy flight crews, although these regulations may be waived during the first 36–48 hours of an amphibious assault (U.S. Congress Office of Technology Assessment, 1991c).

Nuclear Power Plant Workers

Although the dangers of a nuclear power plant accident have been recognized from the industry's inception in the 1950s, regulations have focused exclusively on reactor design, training programs, and licensing requirements. The dangers of operator fatigue were not acknowledged until 1980 (U.S. Nuclear Regulatory Commission, 1980), when the Nuclear Regulatory Commission (NRC) reported that “inspections of personnel performance and training since the accident at Three Mile Island, have shown that in certain situations facility personnel are either required or allowed to remain on duty for extended periods of time.” The NRC recommended that (1) workers not be permitted to work more than 12 hours straight, (2) there be at least a 12-hour break between all work periods, (3) individuals not work more than 72 hours in any 7-day period, and (4) that workers not work more than 14 consecutive days without having 2 days off.

A second generic letter sent 6 months later to all licensees of operating power plants and applicants for operating licenses (Eisenhut, 1980) recommended that enough plant operating personnel be employed to provide adequate coverage without the routine heavy use of overtime, but stated that when unforeseen problems occurred and/or the reactor was shut down for refueling, major maintenance, or major plant modifications, workers could work up to 16 consecutive hours as long as they had a break of at least 8 hours between shifts. In addition, workers could not work more than 24 hours in any 48-hour period or more than 72 hours in a 7-day period. If there were extenuating circumstances, however, the plant manager or his/ her designee could authorize additional hours. Although further clarifications were issued in 1982 (Eisenhut, 1982), no substantive changes were made to these guidelines.

It is important to note that these are guidelines or recommended policies, not regulations. Although the Director of the Division of Licensing, Office of Nuclear Reactor Regulation, can suggest in a generic letter to all licensees of operating plants, applicants for an operating license, and holders of construction permits that they “take action as necessary to revise the administrative section of [their] technical specifications to assure [their] plant administrative procedures follow the revised work hour guidelines” (Eisenhut, 1982), plant owners cannot be compelled to follow those recommendations. Nuclear power plant operators can choose to incorporate the recommendations into their technical specifications and administrative procedures, but are not required to do so (U.S. Congress Office of Technology Assessment, 1991b). Once incorporated into a plant's technical specifications and administrative procedures, however, these policies can be, although rarely are, enforced by the NRC.

Most nuclear power plant employees work 8-hour shifts, although a growing number of power plants have sought permission to implement 12-hour shift schedules (U.S. Congress Office of Technology Assessment, 1991b). Workers usually rotate shifts and have every other weekend off. Overtime is common, especially in outage situations, when every day off line (not functioning) costs the utility revenue (U.S. Congress Office of Technology Assessment, 1991b). Staff shortages, usually associated with an employee failing to show up for a scheduled shift, often result in employees being required to work a double shift (if on 8-hour shifts) or split a second shift with another worker.

Plant workers' claims that they often work more than 70 hours a week when the reactor is operating and 80 or 90 hours a week when the plant is shut down for refueling or other tasks (TiredNukes.Org, 2002) have been substantiated. For example, data collected by the Nuclear Energy Institute showed that one-third of nuclear power plants were authorizing more than 1,000 and as many as 7,500 approvals10 a year to exceed the guidelines (Travers, 2001). In addition, over one-quarter of the sites surveyed reported that more than 20 percent of their personnel covered by the guidelines were working more than 600 hours (per person) of overtime per year (U.S. Nuclear Regulatory Commission, 2000a). This number is more than two to three times the level allowed for operators at some foreign nuclear power plants and more than twice the level recommended by an expert panel in 1985 (NUREG/CR-4248) (U.S. Nuclear Regulatory Commission, 2000a).

Although fatigue was not identified as a causal factor in the Three Mile Island accident, NRC inspectors ruled that fatigue from excessive overtime was the main contributor to an accident at Braidwood Unit 1 in Illinois, where three workers were accidentally sprayed with 180°F water (U.S. Nuclear Regulatory Commission, 1991). Other plants were also criticized in Information Notice No. 91-36 (sent to all holders of operating licenses or construction permits for nuclear power reactors) for using excessive overtime, preparing overtime authorizations after the fact, and maintaining poor documentation of overtime (Union of Concerned Scientists, 2000).

Although concerns about operator fatigue and excessive overtime have been voiced in numerous generic letters and information notices and during the 1990 Fitness for Duty Rulemaking Process, no action was taken until 2001, when the NRC concluded that earlier guidelines had not been “wholly effective” in addressing worker fatigue. Four events occurring within an 8-month period apparently stimulated NRC staff members to begin investigating the impact of worker fatigue in nuclear power plants. In February 1999, the Chairman of the NRC received a letter from three congressmen expressing their concerns about staffing levels and excessive overtime in nuclear power plants (Markey et al., 1999; Travers, 2001). A month later, similar issues were raised by the Union of Concerned Scientists in a report entitled Overtime and Staffing Problems in the Commercial Nuclear Power Industry (Travers, 2001; Union of Concerned Scientists, 2000). Finally, in September 1999, the NRC received a petition for rulemaking (PRM-26-2) (Quigley, 1999).

After reviewing several options, the NRC recommended expanding Part 26 of the Fitness for Duty Program to include a broad range of possible impairments, including fatigue. Rather than imposing absolute limits on the number of hours an individual could work in any 48-hour period, specific restrictions on 16-hour shifts, or annual limits on work hours, the NRC opted to “establish thresholds for work hour controls.” However, no specific thresholds were set or recommended in the NRC's rulemaking plan (U.S. Nuclear Regulatory Commission, 2000b), even though NRC staff considered “the limit of no more than 16 hours in any 24-hour period [was] too high to ensure that personnel [were] not impaired by fatigue,” and that a limit of 72 hours in a 7-day period did not appear adequate to prevent cumulative fatigue. Proposed work hour limits would apply regardless of the plants' operating state (e.g., operating or in outage). Some deviations would be allowed if the plant could demonstrate that the extra hours of work would cause no undue risk.

A final rule is not anticipated until at least December 2003 (U.S. Nuclear Regulatory Commission, 2002). Significant opposition to any efforts to regulate work hours is expected.


Operator fatigue was recognized as a danger over 100 years ago, long before scientists were able to demonstrate the adverse effects of fatigue on performance. Traditional modes of passenger transportation, such as railroads and ships, were the first to be regulated. Aviation and trucking were added to the list of industries with work hour restrictions during the 1930s. The aerospace industry, which developed during the latter half of the twentieth century, has no statutes or regulations limiting work hours.

Despite the Department of Transportation's acknowledgment that current work hour rules are outdated and that fatigue remains a significant factor, none of the regulations or statutes limiting hours of service have been modified since 1989. Attempts to incorporate the findings of recent research on fatigue into hours-of-service regulations have not been successful.

Railroad Employees

Although railroads were the predominant mode of intercity travel at the beginning of the twentieth century, rail travel was dangerous for employees and passengers alike. Between 1902 and 1907, over 19,000 employees and passengers were killed in railroad accidents, and another 276,722 were injured (U.S. Congress Office of Technology Assessment, 1978). Four years later, the number of fatalities had risen to 37,907 and the number of injuries to 516,669. Deaths and injuries did not decline until the early 1920s, when the last of the early safety laws,11 the Signal Inspection Law, was enacted (U.S. Congress Office of Technology Assessment, 1978).

The contribution of fatigue to these early accidents is unknown. Although various sources mention the extended or excessive hours worked by railroad employees of that era (Adams, 1879), the actual hours worked by employees is not known. The 1907 Hours of Service Act limited those who were “engaged in or connected to the movement of trains” to 16 hours of consecutive work and mandated a 10-hour rest break between work shifts (Friends of the Railroad Museum of Pennsylvania, 2002; U.S. Congress Office of Technology Assessment, 1978). Employees connected with “train dispatching and train ordering” were restricted to working no more than 9–13 hours in a 24-hour period (U.S. Congress Office of Technology Assessment, 1978). Employees could not be required or volunteer to either go on duty or remain on duty if these limits would be exceeded.

It is not known how Congress arrived at these limits on railroad employee work hours; there were no studies of fatigue and railroad safety to guide their decision-making process. Perhaps they had read some of the accounts referred to by Munsterberg (1913—as cited in Intermodal Transportation Institute, 2000a): “We have in the literature concerned with accidents in transportation numerous popular discussions about the destructive influence of loss of sleep on the attention of the locomotive engineer.” Or as text from a 1917 U.S. Court Decision12 explains, “It is common knowledge that the enactment of this legislation was induced by reason of the many casualties in railroad transportation which resulted from requiring the discharge of arduous duties by tired and exhausted men whose power of service and energy had been so weakened by overwork as to render them inattentive to duty, or incapable of discharging the responsible labors of their positions.” Even without evidence from research studies, the U.S. Congress and other writers at the beginning of the twentieth century were aware that working for long hours without adequate rest periods had an adverse effect on public safety.

Although some modifications have been made to the Hours of Service Act over the past 95 years,13 the basic provisions remain the same. Railroad employees are entitled to 8 consecutive hours off duty in the preceding 24 hours, or 10 consecutive hours off duty after working 12 consecutive hours (49 U.S.C. 21101(a)). Although compliance with the Hours of Service Act has been quite high (the U.S. General Accounting Office [GAO, 1992] found that 99.4 percent of the time, engineers had been given at least 10 hours off duty following a work shift of 12 or more hours), fatigue-related accidents continue to occur.

Over 30 studies (U.S. DOT, 2002) and numerous reports on fatigue among railway employees have been published since Grant's (1971) initial study. Irregular start times, uncertainty about the time of the next assignment, excessive working hours, long commutes and waiting times before beginning work, unsatisfactory conditions for sleeping at some terminals, and work/rest schedules less than 24 hours in length have been cited as factors contributing to the fatigue experienced by railroad crews (Moore-Ede, 2002; Pilcher and Coplen, 1999; Pollard 1991; Sussman and Coplen, 2002). Even though studies and accident investigations have shown that current hours-of-service regulations are not sufficient to prevent fatigue-related accidents, additional modifications of the Hours of Service Act are not planned.

Barriers to legislative change include labor contracts that maximize employee earnings by placing members on 24-hour call, employee resistance to any measure that would reduce the number of trips made and/or lengthen the intervals between trips since their pay is dependant on the number of trips made, and a culture that promotes “working when you want” (Intermodal Transportation Institute, 2000a; Sussman and Coplen, 2002). The development of new, scientifically based standards is also hampered by a lack of scientific consensus on the best way to manage shiftwork schedules, difficulties in translating research findings into operational environments, and recognition that the wide variety of settings (commuter rail, long-haul freight, and short-haul lines) makes it impossible to develop a single set of standards. Educating employees about fatigue management is considered more acceptable to all stakeholders (e.g., employees, railroad management) than prescriptive hours of service (Sussman and Coplen, 2002). As a result, most railroads now offer training modules in fatigue countermeasures for all employees, scheduled days off, confidential screening for sleep apnea, and improved sleeping facilities at railroad terminals (Intermodal Transportation Institute, 2000a,b). Although the programs are varied in the material presented, scheduling approaches, management of emergencies, and outcomes measured, several best practices have emerged. These include (1) assigned days off, particularly after an extended period of work; (2) allowing napping on duty under predetermined and controlled circumstances; and (3) educational interventions tailored to the needs of employees at a specific location (Intermodal Transportation Institute, 2000a).

Marine Employees

U.S. Coast Guard studies indicate that fatigue is a contributing factor in 16 percent of critical vessel casualties14 and 33 percent of personal injuries (McCallum et al., 1996). Sleep is often severely restricted by traditional watch schedules, particularly the 1-in-4 schedule15 (Comperatore et al., 2001). The 1-in-5 schedule, while allowing for longer periods off duty, still requires crewmembers to start work 4 hours earlier every day. Advancing sleep and wake-up times by 4 hours each day is difficult if not impossible for most people. Long workdays, reduced time between watches, sleep disruptions, and fragmented sleep are also common (Comperatore et al., 1999; U.S. Coast Guard Research and Development Center, 1996). All-hands drills and other conditions further fragment sleep.

Manning requirements for Great Lakes vessels, ocean-going vessels, coastwise vessels (vessels that travel only along the coast), offshore supply vessels, towing vessels, and tankers are spelled out in Title 46 of the United States Code, Part F, Manning of Vessels, Section 8104.16 Until 1990, the regulations, which date back to the early part of the twentieth century, focused more on the numbers and types of crewmembers required (e.g., licensed master, three mates, three or four licensed engineers) than on how long crewmembers could work (Maquire, 1984; NTSB, 2002a). The grounding of the Exxon Valdez on March 24, 1989, dramatically changed 46 U.S.C. 8101–8105. The Oil Pollution Act of 1990, which amended 46 U.S.C. 8101–8104, added specific hours-of-service limitations for licensed individuals and seamen; provisions forbidding deck officers to combine both navigation and cargo watch duties using a 6 hours on, 6 hours off schedule; and a requirement that officers on watch during departures from port be sufficiently rested.

Work hours in port as well as at sea are spelled out in the regulations. Seamen cannot be required to work more than 9 out of 24 hours while in port or more than 12 out of 24 hours at sea (on oceangoing or coastwise vessels of not more than 100 gross tons). Crewmembers on vessels operating in the Great Lakes can work up to 15 out of 24 hours, but cannot work more than 36 out of any 72 hours (Clifton, 2002). Work while anchored in a safe harbor is limited to 8 hours per day.17 Licensed individuals or seamen on oil tankers are not permitted to work more than 15 hours in any 24-hour period or more than 36 hours in any 72-hour period. Administrative duties, whether performed on board or on shore, are to be counted as work by vessel operators.18 Crewmembers on the largest type of ocean-going vessels—those over 200 gross tons—traveling over 600 nautical miles from their home port have the shortest workday of all—8 hours (Clifton, 2002). Workers on other types of vessels are limited to working 12 hours in a 24-hour period. The number of watches per day (e.g., two or three) is also prescribed for vessels of various sizes, and unnecessary work is forbidden if the vessel is in port on Sundays and/or certain holidays. Restrictions, however, can be waived in emergencies, such as if work is necessary for the safety of the vessel or to save a life on board another vessel19 (U.S. Congress Office of Technology Assessment, 1991d). Finally, an officer in charge of a deck watch when a vessel leaves port must have been off duty at least 6 of the 12 hours prior to the ship's departure (U.S. Congress Office of Technology Assessment, 1991d).

These regulations apply to all vessels registered in the United States, as well as those from other countries using U.S. ports. Owners, charterers, or managing operators can face civil penalties if the U.S Coast Guard discovers that work hour limits have been exceeded (Clifton, 2002). Individual mariners are expected to obey work hour limitations and to report suspected watchkeeping and work hour violations to the Coast Guard. Tips are kept confidential, and those who report code violations are protected from discrimination, including discharge, by 46 U.S.C. 2114 (Clifton, 2002).

The Oil Pollution Act of 1990 also directed that the U.S. Coast Guard undertake the development of a research program to establish safe manning levels (U.S. Congress Office of Technology Assessment, 1991a), and that results of research on the effects and reduction of fatigue be disseminated to industry personnel (National Transportation Safety Board, 1990). Although safe manning levels have not been established, research over the past 10 years has confirmed that fatigue among mariners is quite common (e.g., up to 70 percent of Coast Guard personnel showed evidence of compromised alertness [Comperatore, et al., 2001]); very complex; and influenced by a wide variety of environmental, operational, and individual factors (NTSB, 2002a). Specialized programs for fatigue countermeasures have been developed and tested by the U.S. Coast Guard, the Crew Endurance Management System (for members of the U.S. Coast Guard [Comperatore et al., 2001], and the Commercial Mariner Endurance Management System (Comperatore and Kingsley, undated).

The U.S. Coast Guard has also begun working closely with the International Maritime Organization to highlight the issue of fatigue and collaborated in the development of the 1995 Amendments to the International Convention on Standards of Training, Certification, and Watchkeeping for Seafarers (NTSB, 2002a). These regulations, which apply to all employees sailing on ocean-going vessels, specify that an officer in charge of a watch or a rating forming part of a watch be provided with a minimum of 10 hours of rest in a 24-hour period and that two rest periods be given, one of these being at least 6 hours in length (International Maritime Organization, 1995). Section B-VIII/1 of the 1995 Amendments also cautions that “the minimum rest periods specified in Section A-VIII/1 should not be interpreted as implying that all other hours may be devoted to watchkeeping or other duties” (International Maritime Organization, 1995).

Despite efforts to publicize their recommendations and work with industry personnel to implement effective programs for fatigue countermeasures, vessels are still running aground because crewmembers are asleep at the helm. Unfortunately, falling asleep at the helm is not a rare or isolated event. Within a 1-week period in 1999, three fishing vessels out of South-eastern New England ran aground after a crewmember fell asleep at the helm (Harrington, 1999). One of the boats was broken apart by the action of the waves; the other two were severely damaged but salvageable, and two of the three crews had to be rescued by the U.S. Coast Guard.

Long-Haul Truck Drivers

Work hours of long-haul truckers have been regulated since the 1930s, when Congress passed the Motor Carrier Act of 1935. This act authorized economic regulation of the trucking industry and directed the Interstate Commerce Commission (ICC) to establish qualifications and maximum hours of service for drivers working for private and for-hire interstate property carriers and for-hire interstate passenger carriers (Federal Motor Carrier Safety Administration, 1999; United Transportation Union, 2001). Although safety was included in the mission of the ICC, the major focus of the agency in 1935 was on the financial plight of the trucking industry (United Transportation Union, 2001).

By December 1937, the ICC had published its final version of the Hours of Service regulations (Federal Motor Carrier Safety Administration, 1999). Drivers could not be permitted or required to be on duty more than 15 out of 24 hours, only 12 hours of which could be spent working (e.g., loading, unloading, driving, handling freight, preparing reports, preparing vehicles for service, or performing any other duties pertaining to the transportation of passengers or property). The extra 3 hours was intended for meals and rest breaks. The need for off-duty time was also recognized:

It is obvious that a man cannot work efficiently or be a safe driver if he does not have an opportunity for approximately 8 hours sleep in 24. It is a matter of simple arithmetic that if a man works 16 hours a day he does not have the opportunity to secure 8 hours sleep. Allowance must be made for eating, dressing, getting to and from work, and the enjoyment of ordinary recreations.

A 48-hour rest period was mandated once a driver reached the maximum weekly work limit. Weekly on-duty limits were set at 60 hours in any 7 consecutive days or 70 hours in 8 consecutive days, depending on whether the carrier operated 7 days a week or less20 (Federal Motor Carrier Safety Administration, 1999).

Within a year, organized labor and trucking companies had successfully petitioned the ICC to revise the Hours of Service regulations (Federal Motor Carrier Safety Administration, 1999). Revisions to the regulations allowed drivers to work up to 16 hours a day as long as they drove only for 10 of those 16 hours. The mandated rest period was also decreased from 9 to 8 consecutive hours. Total work hours per week remained capped at 60 and 70 hours (3 FR 1875). In 1938, the Hours of Service regulations were modified again, this time allowing an extra 2 hours of driving if drivers encountered “unfavorable weather conditions.” Other exceptions—such as emergency conditions, driver-salespeople, oilfield operations, 100 air-mile radius drivers, retail store deliveries, sleeper berths, operations in Alaska and Hawaii, and nondriving travel time—were later granted (Federal Motor Carrier Safety Administration, 1999). However, no substantive changes were made in the regulations until 1962, when the ICC dropped the 24-hour limit.21 The revised rules retained the 10-hour driving limit and the requirement for an 8-hour rest period. By alternating 10-hour driving periods and 8-hour rest periods, drivers were now legally permitted to drive 16 out of 24 hours (Federal Motor Carrier Safety Administration, 1999). Drivers were to maintain logbooks documenting driving periods and mileage.

Neither the original regulations nor the amendments were based on scientific evidence. Although the ICC expressed hope in 1938 that changes in the Hours of Service regulations would not be used to lengthen drivers' hours, truckers engaged in interstate commerce generally work longer hours than any other group of employees in the United States. Typically paid by the mile and exempt from overtime pay by the Fair Labor Act of 1945 (Federal Motor Carrier Safety Administration, 1999), up to 73 percent of tractor trailer drivers exceed the daily and/or weekly driving limits (Beilock and Capelle, 1987). Not only are hours-of-service violators more likely to speed or drive longer hours when given unrealistic driving times, but they are also more likely to report having fallen asleep at the wheel (Braver et al., 1992). Higher crash rates have also been reported by hours-of-service violators (Braver et al., 1992; Jones and Stein, 1987).

A notice of proposed rulemaking to update the Hours of Service regulations was issued in May 2000, generating over 50,000 comments and significant controversy (NTSB, 2002b). To date, none of the following changes have been adopted: (1) increase the on-duty/off-duty cycle to a normal 24-hour work cycle; (2) increase time off to allow sufficient time for 7 to 8 hours of sleep; (3) require mandatory “weekend” recovery periods consisting of at least 2 nights of recovery sleep to enable drivers to resume baseline levels of sleep structure and waking performance and alertness; (4) address the effects of operations between midnight and 6:00 a.m., requiring off-duty periods that enable restorative sleep by including two consecutive periods between these hours; (5) allow “weekends” of sufficient length to ensure safety and provide adequate protection for driver health and safety; and (6) increase operational flexibility by offering a menu of hours-of-service options customized to different major or distinct operational segments while maintaining an appropriate level of safety (Federal Motor Carrier Safety Administration, 1999).

Aviation Industry

Although Charles Lindbergh was not the first pilot to experience the effects of fatigue, his description of fighting fatigue during his 1927 transatlantic flight graphically illustrates the dangers of tired pilots:

My mind clicks on and off. I try letting one eyelid close at a time while I prop the other with my will. But the effort is too much, sleep is winning, my whole body argues dully that nothing, nothing life can attain is quite so desirable as sleep. My mind is loosing resolution and control. (Printup, 2000)

Lindbergh landed safely near Paris after flying for 33.5 hours. Others have not been so lucky, either flying across the Atlantic or within the borders of the United States. The U.S. Air Mail Service was founded in 1918, 15 years after the Wright brothers' initial flight. Accident rates were extremely high: 31 of the original 40 Air Service pilots died in work-related airplane crashes between 1918 and 1921 (Leape, 1994). Lack of attention to safety and “efforts to meet delivery schedules in all kinds of weather” were believed to be the cause of this extraordinarily high accident rate (Leape, 1994). By 1926, the aviation industry, worried that the airplane would not reach its full commercial value without federal action to improve and maintain safety standards, convinced Congress to pass the Air Commerce Act. This act established the Aeronautics Branch of the Department of Commerce, and charged the Secretary of Commerce with fostering air commerce, issuing and enforcing air traffic rules, licensing pilots, certificating aircraft, establishing airways, and operating and maintaining aids to air navigation (Federal Aviation Administration [FAA], 2002). Lighted airways became more common, and aeronautical radio communications were improved through the use of radio beacons. Hours-of-service limitations were not established by the FAA until 1964 (Patton et al., 2001).

The duty schedules for pilots, air traffic controllers, engineers, flight attendants, airline mechanics, and various other types of crew members are regulated by the FAA under statute 11 C.F.R. 121 (P-S). Rules on duty hours for pilots vary by the size of the flight crew (e.g., one pilot versus a crew consisting of two or more pilots). Pilots working during both scheduled and unscheduled operations (e.g., corporate/executive operations), cannot work more than 8 hours in a 24-hour period if there is only one pilot. When larger flight crews are used, pilots are allowed to work an additional 2 hours (Patton et al., 2001; U.S. Congress Office of Technology Assessment, 1991d). Domestic air carriers are not permitted to issue, and pilots are not permitted to accept, an assignment for a flight if the crew member's total flight time will exceed 100 hours in a calendar month, 30 hours in 7 consecutive days, or 8 hours between required rest periods (U.S. Congress Office of Technology Assessment, 1991a). Rest periods are also mandated and vary according to the length of the scheduled flight time. If the scheduled flight is less than 8 hours in duration, 9 consecutive hours of rest are mandated between flights; if the scheduled flight is 8–9 hours in duration, 10 consecutive hours of rest are mandated; and if the scheduled flight is 9 hours or more in duration, 11 consecutive hours of rest are mandated (U.S. Congress Office of Technology Assessment, 1991a). Longer rest periods are also mandated if pilots exceed the daily flight time limitations because of circumstances beyond their control (e.g., adverse weather conditions). If flight time limitations are exceeded by less than 30 minutes, a pilot cannot be assigned or accept an assignment that does not allow for 11 consecutive hours of rest. If the flight time limitations are exceeded by more than 30 minutes, but less than 60 minutes, 12 consecutive hours of rest are mandated. And when flight time limitations are exceeded by 60 minutes or more, 16 consecutive hours of rest are mandated before the next flight (Patton et al., 2001).

Although commercial airline pilots typically work only 13–15 days a month (Meenan, 1999), there is ample evidence that fatigue remains a significant problem. Surveys, observational data, and anecdotal reports have documented that flight crews frequently experience unintentional sleep episodes while flying (Co et al., 1999; Gander et al., 1991a; Rosekind et al., 2000). Maintenance of vigilance, particularly at night, is quite difficult. Pilots are expected to remain alert despite high levels of automation, low light levels on the flight deck, and regulations that require the pilots to remain in their seats for the duration of the flight unless their absence is necessary for the performance of duties in connection with the operation of the aircraft or biological needs, or if the crew member is taking a rest break and relief is provided. Getting up just to stretch or walk around is not allowed (Circadian Information, 2000; Neri et al., 2002). Non–24-hour duty/rest cycles, circadian desynchronization associated with transmeridian flights, and even time zone changes of only a few hours further compromise the pilot's ability to remain alert (Mann, 1999).

Approximately 21 percent of the incidents reported to the National Aeronautics and Space Administration's (NASA) Aviation Safety Reporting System (ASRS), a confidential self-reporting system for flight crews and others to report difficulties and incidents, are fatigue related (NTSB, 2002a). Data sets for both air carriers (Federal Aviation Regulations [FAR] 121) and commuter and corporate operations (FAR 91/135) contain numerous references to fatigue and difficulties maintaining vigilance (Aviation Safety Reporting System, 1998a,b). Fortunately, only one crash has been attributed to fatigue—that of American International Airways flight 808, which missed the runway at the U.S. Naval Air Station in Guantanamo Bay, Cuba, on August 18, 1993. According to the NTSB's investigation, the probable causes of that accident included the following factors: impairment of the judgment, decision-making, and flying abilities of the captain and flight crew because of fatigue; the captain's failure to properly assess the conditions for landing and maintaining vigilant situational awareness of the airplane while maneuvering onto final approach; his failure to prevent the loss of airspeed and avoid a stall; and his failure to execute immediate action to recover from a stall. Also mentioned in the report were the “inadequacy of the flight and duty time regulations applied to 14 C.F.R., Part 121, Supplemental Air Carrier, international operations and the circumstances that resulted in the extended flight/duty hours and the fatigue of the flight crew members” (NTSB, 1994b; Ranter and Luian, 2002).

John Meenan, Senior Vice President of the Air Transport Association of America, was technically correct when he told a House subcommittee that “there has never been a scheduled commercial airline accident attributed to pilot fatigue”(Meenan, 1999). However, several NTSB reports have played down or omitted the role of pilot fatigue even when the agency's own investigators have considered it a significant factor (Circadian Information, 2000). For example, even though the NTSB report on a China Airlines Boeing 707 flight in February 1985 omitted any mention of crew fatigue, a later analysis of the accident by the Aviation Human Factors Team at NASA concluded that inattention caused by crew fatigue was a key factor in the near disaster. Other accidents in which pilot fatigue played a significant but officially unacknowledged role include the KLM–Pan American collision in the Canary Islands in March 1977; the Eastern Airlines DC-9 crash in Charlotte, North Carolina, in 1974; and the Pacific Southwest–Cessna collision over San Diego in 1978 (Circadian Information, 2000).

Air traffic controllers obviously have an essential role in maintaining airline safety. Almost all air traffic controllers rotate shifts, and are limited to working 10 consecutive hours or 10 hours during a 24-hour period unless they have been allowed a rest period of at least 8 hours before or at the end of the first 10 hours of duty.22 Air traffic controllers, like pilots, must be given at least 1 day off during each consecutive 7-day period (U.S. Congress Office of Technology Assessment, 1991d).

Many air traffic controllers appear to have a significant sleep deficit (Marcil and Vincent, 2000). The air traffic controllers studied by Rhodes and colleagues (1996) obtained only about 6–6.5 hours sleep on day shifts and only about 5 hours sleep when working on night shifts. And controllers may get even less sleep if their mandated rest period of 8 hours falls at a time when it is difficult to sleep. The accident investigation following the crash of a United Airlines DC-8 freighter into the side of a mountain in Utah at 1:38 a.m. in December 1977 revealed that the air traffic controller, who had omitted a critical radial number when giving holding instructions to the pilot, had had approximately 2 hours of sleep prior to starting his second shift that day at 11 p.m. (he had also worked the 7 a.m. to 3 p.m. shift that day) (Circadian Information, 2000).

Aerospace Industry

No regulations or guidelines limit work hour durations in the aerospace industry. Most employees work a traditional 40-hour week, then dramatically increase their hours in the weeks before a launch or during the mission. Early missions were short, lasting only a few hours or days. Today's missions, by contrast, may last weeks or even months, placing more demands on mission control staff and astronauts.

Shuttle launches frequently occur at night, requiring flight controllers at Kennedy Space Center to switch from day to night shifts (Kelly et al., 1993). After launch, responsibility for flight operations switches to the Missions Operations Directorate at Johnson Space Center in Houston, Texas, where three flight control teams (FCTs) are used to staff the Missions Operations Directorate for flights of less than 10 days. When flights of 10 days or longer are planned, a fourth FCT is added to allow team members time off. Although shift lengths vary, 10-hour shifts are not uncommon. Flight controllers average less than one break per shift (range 0.1 to 0.9) (Kelly et al., 1993).

Although the explosion of the Challenger space shuttle occurred during the daytime, the decisions made the night before the launch by mission control staff have been cited as a major factor contributing to the explosion (Mitler et al., 1988). Flight controllers are responsible for a wide range of cognitive tasks, including sustained trend analysis, monitoring of multiple voice channels, and rapid responses to emergency situations. Cognitive processing and vigilance must remain high because even small mistakes can be operationally significant (Kelly et al., 1993).

Although the aerospace industry has a history that includes several accidents and near accidents associated with fatigue, there are no regulations on how long workers employed by NASA and/or manufacturers supplying spacecraft components may work in the days prior to or during a mission. In contrast, the sleep patterns of astronauts have been monitored since the early days of the space program (Aschoff, 1965; Pittendrigh, 1967). Several passages from Apollo 13 (Lovell and Kluger, 1994) illustrate the attention paid to the sleep/wake patterns of astronauts during a mission:

After just a day or so in translunar drift, the astronauts got accustomed to the constant flickering and went about their sleep-wake, work-rest schedules as if the sun were rising and setting outside their craft just as it did outside their homes in Houston. As long as the crew maintained that schedule, NASA's flight surgeons had learned, their circadian rhythms would remain largely un-disturbed.

Even on a routine flight, no one expected the pilots to sleep a full eight hours. The almost total lack of physical exertion in space and the almost constant output of adrenaline that accompanied the business of flying to the moon made five or six hours of sack time the most the medics could hope for. Those five or six hours, however, were absolutely essential if a crew that was flying even a nominal mission was going to make it through their day without making some serious, and perhaps disastrous, mistake. A crew that was flying a less than nominal mission would need even more rest. (Lovell and Kluger, 1994:202)

In the second row of Mission Control, the flight surgeon had been copying down the answers the men gave, and the totals had begun to alarm him. Since Monday night, the crew had been averaging about three hours of sleep apiece per day. It was 2:30 Friday morning…. (Lovell and Kluger, 1994:313)

These anecdotal reports of shortened sleep times have been confirmed by both subjective and objective studies (Dijk et al., 2001; Frost et al., 1976, 1977; Grundel et al., 1993, 1996, 1997; Monk et al., 1998; Santy et al., 1998). Despite preflight circadian adaptation measures and in-flight schedules to optimize circadian adaptation and minimize sleep loss, astronauts typically sleep only 6 to 6.5 hours. Polysomnography (sleep studies using electroencephalogram [EEG], electro-occulogram [EOG], and electromyogram [EMG] recordings) have shown more wakefulness and less slow-wave (deep) sleep in the final third of sleep episodes while in space and marked increases in rapid eye movement (REM or dreaming) sleep after return to earth (Dijk et al., 2001).

Astronauts frequently use hypnotics during flights (Putcha et al., 1999), and stimulants are available to ensure alertness during critical phases of the mission. Like Air Force pilots, as discussed earlier, astronauts are allowed to decide whether to take stimulants (usually dextroamphetamine). A final selection from Apollo 13 illustrates one astronaut's decision-making process regarding the use of stimulants:

In the spacecraft, Lovell, Haise, and Swigert were in their accustomed places, all awake and all feeling reasonably alert. Lovell had decided against the Dexedrine tablets Slayton had prescribed for his crew last night, knowing that the lift from the stimulants would be only fleeting, and the subsequent letdown would leave them feeling even worse than they did now. For the time being, the commander had decided, the astronauts would get by on adrenaline alone. (Lovell and Kluger, 1994:318)


Fatigue countermeasures programs usually consist of an educational component (Comperatore and Kingsley, undated; Comperatore et al., 2001; Intermodal Transportation Institute, 2000a; NASA Ames Research Center, 1997; Smith-Coggins et al., 1997) and sometimes include schedule alterations (Intermodal Transportation Institute, 2000a; Sussman and Coplen, 2002). Employees are generally given information about circadian rhythms, sleep hygiene measures, shiftwork and its adverse affects, and a variety of strategies that can be used to counter fatigue (e.g., judicious use of caffeine, napping during night shifts) (NASA Ames Research Center, 2001; Rosekind et al., 1997). Some industries have also added information about sleep disorders to their presentations (Intermodal Transportation Institute, 2000a). Managers are urged to consider altering the starting times of shifts whenever possible to make schedules more compatible with circadian rhythms; to avoid scheduling employees to work more than two or three consecutive night shifts; and to provide adequate recovery times between shifts, especially when an employee is rotating off night shift. By 1997, 497 people from 230 organizations in 17 countries had participated in a 2-day trainers' workshop run by the NASA Ames Fatigue Countermeasures Group (NASA Ames Research Center, 1997). Attendees have included representatives from all areas of aviation; other modes of transportation, including the rail, trucking, and maritime industries; health care; the petrochemical industry; nuclear energy; and law enforcement. Follow-up data gathered from workshop attendees suggest that over 125,000 flight crews and other employees, including some physicians, have received educational materials on combating fatigue.

Although over 170,000 employees have been exposed to fatigue countermeasures programs, there is very limited information about their efficacy. Typical reports indicate that some aspects of a particular program were successful (e.g., employees slept longer at night [Pollard, 1991], napping improved alertness on duty [Neri et al., 2002])], and that participants used most of the suggested strategies (Smith-Coggins et al., 1997), but rarely assess the overall efficacy of programs in improving alertness on the job and/or reducing errors.

Smith-Coggins and colleagues (1997) found that, although resident physicians (n = 6) reported increased subjective alertness after using the suggested strategies for 1 month, there were no improvements in their performance, mood, or amount of sleep obtained when working night shifts. To date, no one has tested the efficacy of this type of intervention in a population of hospital staff nurses. A fatigue countermeasures program for nurses is currently being developed at the University of Pennsylvania, and will soon be tested using nurses from four ICUs (two control and two intervention). Subjective and objective measures of alertness and vigilance will be obtained before the program is implemented and 4 weeks following implementation. Although errors and near errors will also be recorded during the baseline and later data collection periods, this pilot study may not have sufficient power to detect changes in error rates.


Hours-of-service regulations have not always emerged from the results of rigorous scientific research. Many of the original regulations were written in response to a disaster, such the grounding of an oil tanker or the death of young woman (Libby Zion) in a New York City hospital, or to protect a particular industry or group of employees (e.g., trucking and manning rules for seagoing vessels). Amending existing hours-of-service regulations has often been a difficult if not impossible undertaking, even when the proposed changes are supported by scientific evidence. Employees, unions, owners, and professional associations often oppose any regulation that is perceived to reduce the earning power of employees, involve hiring more employees, or cost more money.

Guidelines, which are more flexible than regulations, are not enforceable and do not prohibit employees from working for long periods each day and/or accruing large amounts of overtime. Other regulations, such as driving-time limits for truckers, although enforceable, are easily circumvented. Fatigue countermeasures programs, which require employees to take responsibility for acquiring sufficient sleep and remaining alert on the job, are often used in place of and along with hours-of-service regulations.

Although no particular approach, whether work hour regulation, guidelines, fatigue countermeasures programs, or some combination of these, can be applied to all industries or all settings within a particular industry, there appears to be some agreement that working longer than 12 consecutive hours without at least 8 hours off duty can be hazardous. Accident rates rise exponentially after 12 hours of work, particularly when employees work at night. Some work environments limit nighttime workers to shorter shifts (e.g., 8 hours) or consider 1 hour of nighttime flying to be equal to 1.4 hours of flight time during the day (U.S. Army). Many industries in which fatigued employees could compromise public safety do not allow employees to work more than 8–12 consecutive hours.

More research is needed to understand the effects of fatigue on patient safety. Controlled trials are needed to determine optimal work schedules in hospital settings and to test fatigue countermeasures. According to Olson and Ambrogetti (1998): “We do know enough to end the worse abuses of the human sleep-wake cycle, and we need to see a shift by both hospital employers and the medical [nursing] profession towards addressing this issue.” The authors of the early hours-of-service regulations understood that people cannot work for long periods of time each day without adequate time to sleep. It is perhaps time to acknowledge that nurses cannot provide safe care when they are fatigued, have worked for more than 12 hours, and/ or have not had at least 12–16 hours off between shifts.


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This appendix was prepared for the committee to inform its deliberations by Ann E. Rogers, Ph.D., R.N., F.A.A.N., of the University of Pennsylvania School of Nursing.


Safe Nursing and Patient Care Act of 2001. S. 1686, H.R. 3238 (2001).


Registered Nurses and Patient Protection Act. H.R. 1289 (2001).


New York State Health Code. The Bell Regulations. N.Y.C.R.R. § 405.4 (1989).


Meperidine is contraindicated for a patient taking phanelzine.


Hospital Association v. Axelrod, 546 N.Y.S.2d 531. 1989.


The Patient and Physician Safety Act of 2001. S. 2614, H.R. 3236 (2001).


Bill Summary and Status for the 107th Congress (2002).


Bill Summary and Status for the 107th Congress (2002).


An approval by the plant manager is required every time a worker is asked to work more than 12 hours/day, more than 72 hours/week, or more than 14 consecutive days. Therefore, one-third of the plants studied were authorizing between 3 and 21 workers/day to exceed work hour guidelines.


Other measures included the Hours of Service Act of 1907; the Ash Pan Act, designed to prevent injury to workers cleaning ashes from engines not equipped with ash pans; the Safety Appliances Act, requiring standardized equipment for breaking, couplers, and handholds; the Block Signal Act, which provided incentives for the testing and installation of automatic signaling devices; and the Locomotive Boiler Inspection Act.


Atchison Topeka and Santa Fe Railroad Co. v. United States No. 267. U.S. Supreme Court (1917).


Hours of Service Act. C.F.R. Title 49, Volume 4, Parts 200–399, Chapter 211 (1994; Revised October 1, 1996), and Rail Safety Enforcement and Review Act. 106 S. 972 (1992).


Defined as severe damage to the vessel, capable of causing crew fatalities.


A 1-in-4 watch schedule requires crew members to work two 4-hour periods the first day (e.g., 2400–0400 and 1600–2000), and one 4-hour period the next (0800–1200). A 1-in-5 schedule requires crew members to stand watch from 2400 to 0400 and from 2000 to 2400 on the first day, from 1600 to 2000 the second day, from 1200 to 1600 the third day, from 0800 to 1200 on the fourth day, and from 0400 to 0800 on the fifth day.


1990 Amendment, Manning of Vessels. United States Federal Regulations 46, 8101–8104 (1990).


1990 Amendment, Manning of Vessels. United States Federal Regulations 46, 8101–8104 (1990).


1990 Amendment, Manning of Vessels. United States Federal Regulations 46, 8101–8104 (1990).


1990 Amendment, Manning of Vessels. United States Federal Regulations 46, 8101–8104 (1990).


If a carrier operates 7 days a week, a driver may work 70 hours in 8 consecutive days. If a carrier operates less than 7 days a week, a driver may work only 60 hours in 7 consecutive days.


“Hours of service” 49 C.F.R. Part 395 (1962).


Certification: Airmen Other than Flight Crewmembers. 14 C.F.R. 65.47.

Copyright 2004 by the National Academy of Sciences. All rights reserved.
Bookshelf ID: NBK216189


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