Work-related fatigue has been estimated by the National Safety Council to cost employers approximately $151 billion annually in reduced productivity related to sleep deficiencies, sleep disorders, and shift work. However, this is just a fraction of the true cost, as chronic sleep deprivation and nonstandard work schedules have been linked with increased risk of depression, obesity, cardiovascular disease, cancer, and other illnesses with ultimate effects on work productivity, worker health, and safety. Fatigue can slow reaction times, reduce attention or concentration, limit short-term memory, and impair judgment, increasing the risk for fatigue-related incidents such as work injuries. Work-related fatigue can also have a devastating public safety impact, particularly in occupations with high-risk consequences. For example, the nuclear meltdown at Three Mile Island and the grounding of the Exxon Valdez oil tanker are two major disasters in which human fatigue was cited as a contributing factor. On a more frequent scale, tired workers drive on public roads, raising public health and safety concerns. Specifically, drowsy driving increases the risk for motor vehicle crashes by 250 percent and results in $109 billion in societal costs every year due to fatalities and injuries from fatigue-related crashes (see publications from SLEEP and the Governors Highway Safety Association, listed under “Resources” below).

Overnight, rotating, or irregular shifts; long work hours; and resulting sleep impairment or disruption often contribute to work-related fatigue. It has been estimated that almost 30 percent of U.S. workers are employed in schedules that are outside a “regular daytime shift” and 37 percent of workers get less than the recommended seven hours of sleep (see data from NIOSH Worker Health Charts and a consensus statement published in the Journal of Clinical Sleep Medicine in the “Resources” section). According to research published in Occupational and Environmental Medicine, while just over 50 percent of night shift workers report not getting sufficient sleep, almost 33 percent of day shift workers also report obtaining less than seven hours of sleep per night—numbers that suggest this problem can affect any worker, regardless of work schedule. A survey of causes and consequences of employee fatigue published by the National Safety Council found that 43 percent of U.S. workers do not get enough sleep such that it affects their ability to perform critical tasks, which can affect not only their safety at work but also that of their coworkers. The same survey found that 90 percent of employers felt that work-related fatigue had negatively impacted their organizations in terms of reduced productivity and absenteeism. Half of surveyed employers reported they would adjust an employee’s schedules or tasks to reduce the risk of fatigue-related, safety-critical events. However, more than 70 percent said that they typically issue a warning or disciplinary action, suggesting that workplace mitigation strategies for fatigue may more often involve reactive, punitive measures rather than prescriptive or preemptive organizational control strategies. Fatigue is pervasive and nondiscriminating, potentially affecting any worker at any job in any organization. However, despite its high prevalence and increased risk of severe and widespread adverse occupational health and safety consequences, fatigue is not treated with the same industrial hygiene approach as other workplace hazards. A UNIQUE AND COMPLICATED HAZARD On the surface, work-related fatigue may appear to be simple to address and mitigate. Fatigue is multifaceted and can stem from various work and nonwork factors. In the occupational realm, we are familiar with factors such as work schedules, workload, and work intensity, but there are factors specific to individuals, such as age, that can also have a significant effect on fatigue at work. Life or lifestyle factors such as commuting or caring for dependents can be additional stressors and require extra time from already busy days. A common strategy to mitigate work-related fatigue is to change hours of work or encourage workers to get enough sleep. However, work-related fatigue is complicated and poses several challenges to address from an industrial hygiene perspective. Several factors can contribute to fatigue, which makes it difficult to quantify or evaluate with a single standard measure. Unlike work hazards like chemical or biological exposures, there are no threshold levels, making it difficult to determine “how much is too much.” An article published in 2017 in Consulting Psychology Journal: Practice and Research finds that among the biggest challenges in managing work-related fatigue are the pervasive attitudes perpetuating long work hours and unhealthy sleep beliefs and behaviors, which often emanate from the leadership level. Since there is such a wide variability of these factors across sectors, organizations, and individuals, there is no one consistently effective solution that can fit all situations. APPLYING THE FOUR TENETS OF IH An industrial hygiene approach can be used in the anticipation, recognition, evaluation, and control of factors contributing to work-related fatigue to help address these challenges. Anticipation of a workplace hazard begins with a worksite analysis to identify what activities and areas are susceptible to hazardous conditions. In the case of work-related fatigue, this involves identifying potential sources like work scheduling, job tasks (physically or mentally demanding or monotonous work, for example), and environmental factors such as heat or noise. Discussions with management, safety professionals, and workers within the organization can provide additional information on circumstances surrounding events such as near misses or unreported incidents. Incident reports can also help to identify main contributors of work-related fatigue. Provision of educational resources about sleep and fatigue, such as the NIOSH online training for nurses on shift work and long work hours, may help workers recognize sources of fatigue outside of the workplace.

IMELDA WONG, PhD, is coordinator of the NIOSH Center for Work and Fatigue Research.