Sleep and Work

We know that sleep is important.  The need for sleep is biologically similar to the need to eat and drink, and it is critical for maintaining life and health and for working safely.  Sleeping 7 to 8 hours a night is linked with a wide range of better health and safety outcomes. NIOSH has been actively involved in research to protect workers, workers’ families, employers, and the community from the hazards linked to long work hours and shift work. In honor of National Sleep Awareness Week, we have summarized the sleep and work issue below and, in a companion blog tomorrow, will highlight NIOSH research in this area.

A growing number of American workers are not getting enough sleep. Research shows an increase from 24% in the 1980s to 30% in the 2000s in the percentage of American civilian workers reporting 6 or fewer hours of sleep per day—a level considered by sleep experts to be too short (Luckhaupt, Tak, & Calvert 2009).

Why are more Americans getting less sleep? Work demands are one factor. The timing of a shift can strain a worker’s ability to get enough sleep. Working at night or during irregular hours goes against the human body’s biology, which is hard-wired to sleep during the night and be awake and active during the day. Still, society needs certain workers around the clock to provide vital services in public safety, healthcare, utilities, food services, manufacturing, transportation, and others. The resulting shift work—any shift outside the normal daylight hours of 7 a.m. to 6 p.m.—is linked to poorer sleep, circadian rhythm disturbances, and strains on family and social life. It is not possible to eliminate shift work altogether, so the challenge is to develop strategies to make critical services available while keeping workers healthy and everyone around them safe. In addition to shift work, some data suggest that a growing number of employees are being asked to work long hours on a regular basis. Every extra hour on the job is one less spent attending to the person’s off-the-job responsibilities. When the day is too full to fit everything in, it is often sleep that gets the short shrift.

What are the risks of long work hours and shift work?

Risks for Workers:

• Sleep deprivation
• Lack of adequate time to recover from work
• Decline in mental function and physical ability, including emotional fatigue and a decline in the function of the body’s immune system
• Higher rates of depression, occupational injury, and poor perceived health
• Higher prevalence of insomnia among shift workers with low social support
• Increased risk of illness and injury
• Strain on personal relationships, such as marriage and family life
• Increased risk of long-term health effects, such as heart disease, gastrointestinal disorders, mood disturbances, and cancer

Risks for Employers:

• Reduced productivity
• Increase in errors
• Absenteeism and presenteeism (present at work but not fully functioning because of health problems or personal issues)
• Increased health care and worker compensation costs
• Workforce attrition due to disability, death, or moving to jobs with less demanding schedules

Risks to the Community:

• Potential increase in errors by workers leading to:
  • Medical errors
  • Vehicle crashes
  • Industrial disasters

Research indicates that the effect of long work hours and shift work may be more complex than a simple direct relationship between a certain high number of work hours or shift schedule and risks. The effects appear to be influenced by a variety of factors including characteristics of the worker and the job, worker control, pay, non-work responsibilities, and other characteristics of the work schedule.

Both workers and employers share in the responsibility of reducing risks connected to poor sleep. Therefore, it is important for both workers and managers to make sleep a priority in their personal life and in the assignment of work.

What can employers do to address this issue?

• Regular Rest: Establish at least 10 consecutive hours per day of protected time off-duty in order for workers to obtain 7-8 hours of sleep.
• Rest Breaks: Frequent brief rest breaks (e.g., every 1-2 hours) during demanding work are more effective against fatigue than a few longer breaks. Allow longer breaks for meals.
• Shift Lengths: Five 8-hour shifts or four 10-hour shifts per week are usually tolerable. Depending on the workload, twelve-hour days may be tolerable with more frequent interspersed rest days. Shorter shifts (e.g., 8 hours), during the evening and night, are better tolerated than longer shifts.
• Workload: Examine work demands with respect to shift length. Twelve-hour shifts are more tolerable for “lighter” tasks (e.g., desk work).
• Rest Days: Plan one or two full days of rest to follow five consecutive 8-hour shifts or four 10-hour shifts. Consider two rest days after three consecutive 12-hour shifts.
• Training: Provide training to make sure that workers are aware of the ups and downs of shiftwork and that they know what resources are available to them to help with any difficulties they are having with the work schedule.
• Incident Analysis: Examine near misses and incidents to determine the role, if any, of fatigue as a root cause or contributing cause to the incident.

What can workers do to address this issue?

• Make sure you give yourself enough time to sleep after working your shift.
• Avoid heavy foods and alcohol before sleeping and reduce intake of caffeine and other stimulants several hours beforehand since these can make it difficult to get quality sleep.
• Exercise routinely, as keeping physically fit can help you manage stress, stay healthy, and improve your sleep.
• Choose to sleep someplace dark, comfortable, quiet, and cool so you can fall asleep quickly and stay asleep.
• Seek assistance from an appropriate healthcare provider if you are having difficulties sleeping.

What does the future hold?

NIOSH is working on several projects to reduce the risks associated with long working hours and shiftwork. Our current research includes:

• Studying new methods to better measure work hours
• Surveillance to better understand the extent of the problem
• Studies to estimate risks to workers and employers
• Training interventions

Stay tuned for another blog tomorrow summarizing NIOSH research efforts related to sleep and work. The NIOSH Work Schedules topic page also includes helpful resources.

—Claire Caruso, PhD, RN, and Roger R. Rosa, PhD

Dr. Caruso is a research health scientist in the NIOSH Division of Applied Research and Technology.

Dr. Rosa is the NIOSH Deputy Associate Director for Science.