Shift work refers to a work schedule that is different from the traditional eight-hour, five-day-per-week daytime schedule. Examples of shift work include evening and night shifts, compressed schedules (fewer than five days, more hours per day), and shift schedules that rotate (working daytime for a period and then moving to evenings or nights or working the same shift but rotating days off). Shift work is common in a number of occupations that require round-the-clock operations such as public safety, medicine (doctors, nurses, technicians, and so on), and transportation (trucking, airlines, and so on) as well as mining and manufacturing, where full-time operations are necessary for profit making.
A significant amount of research has been conducted on the impact of shift work in the areas of medicine, transportation, and manufacturing, whereas there has been limited attention paid to shift work in public safety, even though the potential for harm may be equally or more pronounced. Much of the accumulated evidence on the impact of shift work has led to greater regulation of work hours and schedules in some fields in order to protect the public and improve worker safety. Needless to say, law enforcement schedules and hours are not regulated, although many agencies have adopted policies limiting work hours per day, pay period, or month.
What Is Fatigue?
Fatigue is the subjective experience of being persistently tired, weak, weary, or exhausted mentally and/or physically (Dittner, Wessely, and Brown 2004). Fatigue is often either a characteristic of, or contributor to, various diseases and conditions including chronic fatigue syndrome (CFS), cancer, multiple sclerosis, and depression (Dittner, Wessely, and Brown 2004). Fatigue is often the result of overexertion both mentally and/or physically, but interestingly can also be caused by boredom.
Rosekind and his colleagues (1994) asserted that sleep loss and circadian disruption are the two principal physiological sources of fatigue. Other nonprimary causes of fatigue include long and irregular work hours, moonlighting, shift work, stress, and poor sleep quality (Vila 2005). Fatigue is also a fundamental source of stress among police (see, for example, Brown and Campbell 1994; Burke 1994; Violanti and Aron 1993). Shift rotations or changeovers to new shift schedules can disrupt circadian rhythms and sleep length, thereby resulting in fatigue. Shift changes and extended shifts lead to increased fatigue, and according to Worden (1995), it is common for police to work double shifts due to staffing needs of community policing demands. Additionally, agency demands and required court appearances may lead to the need for increased overtime on the part of officers, thereby lengthening their shifts.
The Effects of Fatigue
Across a broad array of occupations, it has been reported that chronic sleep restriction in which one gets fewer than seven hours of sleep per night for an extended period has been shown to be associated with on-the-job errors, injuries, traffic accidents, personal conflicts, health complaints, and drug use (Dinges, Rogers, and Baynard 2004). It has been well established that increased fatigue worsens mood, decreases alertness, impairs performance, adds to the likelihood of poor judgment, and can lead police to misuse of force (Vila 1996; Vila et al. 2000). Fatigue may also impact family relationships as well as officer stress and associated reactions. According to Vila (2005), fatigue in police undermines justice by reducing humanity (depriving them of health and ability to reason); reduces attentiveness, the ability to temper frustration, and the ability to regulate; increases fear, anxiety, and proneness to anger; and narrows perspective, thereby impacting decision making.
In a recent national study of work schedules and fatigue in major police agencies, researchers found that officers who routinely worked more consecutive hours than would be legal in other public service industries were six times more fatigued than those in industrial and mining jobs (see Vila et al. 2000). The study also revealed that 14% of officers reported being tired regularly and 16% had trouble staying awake at work.
There are two variables to consider when examining the effects of fatigue from shift work. The first has to do with the time of day of the shift. Studies have shown that the performance of those working the night shift is slower and less accurate (Smith, Totterdell, and Folkard 1995) and results in poor sleep (less sleep time and that of a lesser quality) primarily due to problems associated with circadian rhythms. However, a recent study showed that officers were more willing to shoot and less likely to take cover in a “difficult to justify” shooting simulation during the early day shift (beginning at 6:00 a.m.) as compared to the evening or midnight shift.
The other important variable to examine when evaluating the effects of fatigue is the length of the shift. In a review article, researchers concluded that the results across studies are equivocal, with few differences between eight- and twelve-hour shifts, although they noted that fatigue and safety are concerns with twelve-hour shifts (Smith et al. 1998). In a more recent report from the National Institute for Occupational Safety and Health (NIOSH), researchers indicated that “a pattern of deteriorating performance” is observed across studies, particularly when combining twelve-hour shifts with more than forty hours of work per week (Caruso et al. 2004). Evidence does suggest that fatigue is linked to long working hours, but there is not conclusive evidence on the number of hours it takes for an individual to become fatigued (White and Beswick 2003).
Effects of Fatigue on Cognitive Functioning
Fatigue can interfere with decision making by limiting the formation of sound decisions, encouraging overly constrained choices, and inducing poor responses due to increased irritability (Vila et al. 2000).
Research suggests that fatigue can narrow one’s perspective, increase anxiety and fearfulness, and limit one’s ability to handle complex, stressful situations. In fact, Dawson and Reid (1997) reported that twenty-four hours of sustained wakefulness decreases performance to a level equivalent to a blood alcohol concentration of .10%, which in all U.S. jurisdictions is considered legally drunk.
Effects of Fatigue on Performance
Fatigue has been linked to vehicle and on-the-job accidents in many occupations. However, there has been little research among law enforcement. Nevertheless, a greater proportion of police officers are killed in vehicle accidents, falls, and accidental shootings today since the 1970s, when soft body armor was widely adopted. Given that accidents are more dangerous to police than gunfights, domestic disturbances, arrests, and traffic stops, it is perhaps more important than ever that we examine the link between fatigue and accidents among police. One study found that those officers who reported being tired at the beginning of their work shifts were more likely to be involved in accidents (Vila et al. 2000).
Measurement of Fatigue
A large number of scales have been developed to assess the nature, severity, and impact of fatigue (Dittner, Wessely, and Brown 2004). However, the majority of the measures are designed for use with clinical populations rather than the general population. As such, numerous instruments exist for measuring fatigue in those patients with cancer, depression, chronic fatigue syndrome, multiple sclerosis, and other illnesses. Nevertheless, the measurement of fatigue generally focuses on both acute fatigue (often experienced at the end of a long day) and cumulative fatigue (experienced even after a good night’s sleep).
Fatigue can be measured both subjectively and objectively. One such subjective measure of fatigue is the Pittsburgh sleep quality index (PSQI), a global index measuring sleep quality, sleep latency (time to fall asleep), sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction (Buysse et al. 1989). This measure is often used as a measure of fatigue. An example of an objective measure of fatigue is the fitness-for-duty (FIT) workplace screener, a noninvasive eye reaction test that taps into the influence of fatigue on involuntary eye reactions to light, so the responses are not consciously controlled by the participant (see, for example, Krichmar et al. 1998).
In policing, early detection of fatigue is essential for preventing accidents, injuries, or other forms of behavior that could be detrimental. While coworkers and supervisors may be the most capable of observing fatigue among fellow officers, a properly designed and implemented early warning and intervention system may be useful in identifying those officers whose performance may indicate an underlying fatigue problem. Proper controls ought to be implemented to assess the amount of overtime that officers work, and systems should be in place to account for off-duty employment (that is, moonlighting). In combination with other routine officer stress factors, fatigue can be very detrimental to officers if they are unable to cope with the stress of the job or get enough sleep to ensure health and safety.
While the impact of fatigue on police officers can have dire consequences, Vila (2005) argues that much of fatigue is avoidable and that there are ways to control it. He notes that practitioners and administrators see fatigue as part and parcel of the police environment, making it easy to ignore. Our expectations of police both emotionally and physically are often unrealistic. Yet Vila asserts that by initiating organizational work hour policies and reduced demands for overtime or double shifts, much of police fatigue can be organizationally controlled.