TABLE 1.

Some of what we know about disproportionately at-risk populations, working hours, and fatigue

Characteristic	Differential exposure to working hours	Differential risk of fatigue
Sex	Female workers are more likely to work permanent, including permanent day shifts, perhaps reflecting childcare expectations.48–51	Female workers need to sleep longer, and report more sleep problems52–57 and fatigue than male workers53,58; they may be more susceptible to fatigue.59–66
	A greater proportion of male workers are exposed to night work in both Canada and the United States.67	Female workers are more likely to have social support networks to protect against fatigue and occupational stress; male workers may have higher shift work tolerance.56
		Male shift workers engage in more disengagement styles of coping which is associated with hardiness.68
Age (younger workers)	Younger workers may have no seniority at work and may have little to no control to select their working schedule.	Younger workers have an increased likelihood of experiencing fatigue due to physical and cognitive developmental and social factors.69,70
	Younger workers fear refusing to accept long or irregular hours may jeopardize their jobs.	Younger workers may be more robust to the effects of fatigue and able to recover more quickly.56,71–79
Age (older workers)	Older workers may have seniority at work and be able to select their working schedule.50	Sleep duration,80 sleep content, and fatigue recovery vary across lifespan.81–83
	Older workers fear refusing to accept long or irregular hours may jeopardize their jobs.56	Sleep time decreases with age, and insufficient sleep is positively associated with older age74; older workers experienced more fatigue.76
	Healthy shift work effect: older workers who remain in jobs with long working hours may be healthier and may be able to cope better.56	Adaptation to night shift is poorer at increasing age71; reduced tolerance to shift work around age 40–50.56
Contingent/temporary status	Temporary workers have little or no control over work schedule.84	Temporary workers reported long/irregular/unpredictable work hours, lower control over work hours, and more work-life conflict. Health-related concerns related to work-life conflict included fatigue, sleep disturbance, lack of exercise & poor diet.85
	Temporary workers have unpredictable work hours.85
Minority status	Latinos and Blacks work disproportionately more during evening/late night and midnight hours.51	Race is a social construct and not a biological grouping and therefore may reflect different coping strategies due to socioeconomic health disparities due to racism.
	Black/African American workers are more likely to perform work with rotations50,51; Black and Hispanic minorities have less flexible/less control over schedules than white workers.86
Immigration status	Immigrants tend to work more often in “dirty, dangerous, and demeaning” (3D) jobs which tend to also involve fatigue-inducing work hours.87 Immigrants fear refusing to accept long or irregular hours may jeopardize their jobs.88	Immigration status may impact coping strategies for fatigue management, by limiting access to health, social, and financial resources as well as alternative employment opportunities.
Small business employment	May face increased exposure to fatigue-inducing hours at work. Small businesses are more likely to hire other workers from other at-risk groups.	Small business employees may not have access to the same type of employee support for fatigue management.
Education level or lacking qualifications	Workers with lower education levels fear refusing to accept long or irregular hours may jeopardize their jobs.76 Long working hours and shift work are more common in occupations that do not require advanced degrees89; workers' education influences access to flexible schedules/control over working hours.86	Education may impact coping strategies for fatigue management, by limiting access to social, health, and financial resources, as well as alternative employment opportunities.
	Shift work comes with a higher income than standard jobs that require higher education levels.
Low income	Financial need may increase likelihood of accepting long or irregular shift hours, which tend to come with a pay premium.76,90 Workers with family incomes below the poverty level are more likely to work at nonstandard times.	Income may impact coping strategies for fatigue-management, by limiting access to health, social, and financial resources as well as alternative employment opportunities.
	Working nonstandard hours allows for “moonlighting” more easily.76