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Fleet | Fatigue | Worker health and wellness | Hours of service | Injury prevention
FATIGUE AFFECTS REACTION TIME, MOTOR SKILLS

Sleepy and unsafe

Why aren't workers getting enough rest?

May 23, 2014

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Key points

  • Sleep deprivation can hinder the ability to work safely by significantly reducing reaction time, motor control, decision-making and situational awareness.
  • Over time, workers become very limited in their ability to detect how sleepy they actually are.
  • According to experts, many employees choose to forgo sleep to spend more time on work and with family and friends.

Research has shown that inadequate sleep can affect workers’ ability to remain healthy and perform their work safely – and in safety-sensitive positions, can even put others in harm’s way.


  • A 2012 survey conducted by the Arlington, VA-based National Sleep Foundation found that 11 percent of transportation workers polled admitted showing up to work feeling sleepy. Additionally, 20 percent of pilots and train operators and 15 percent of truck drivers said lack of sleep had directly caused at least one serious incident or near miss in their careers.
  • A study published in the Journal of Occupational and Environmental Medicine (Vol. 54, No. 7) concluded that sleep deficiency was associated with higher rates of musculoskeletal pain and functional limitations among health care workers. Researchers from the Harvard School of Public Health Center for Work, Health and Well-Being found that more than half of nurse participants were sleep-deprived and three-fourths reported pain, with some indicating that the pain interfered with their work.
  • A study from researchers at Brigham and Women’s Hospital in Boston found that workers who rely on visual perception – including power-plant monitors, air-traffic controllers and baggage screeners – are at risk of not being able to perform their work adequately if they become sleep-deprived. As part of the study, published in the Journal of Vision (Vol. 12, No. 7), participants who were asked to sleep for less than six hours a night for several weeks became slower at identifying visual information in computerized tests even though they reported feeling little difference in sleepiness.

Inadequate sleep affects many essential aspects of working safely, according to Thomas Balkin, chief of the Department of Behavioral Biology at the Walter Reed Army Institute of Research and former chairperson of the board of directors for the National Sleep Foundation. Sleep deprivation can significantly reduce workers’ reaction time, motor control, decision-making ability and situational awareness, Balkin said.

Are your workers sleep deprived?

A study on fatigue risk management in workplaces, published in the Journal of Occupational and Environmental Medicine (Vol. 54, No. 2), identified the following signs that an employee’s sleep may be compromised:

Physical signs – Frequent yawning, drooped head or eyelids, rubbing one’s eyes, and microsleeps (unnoticed periods of sleep lasting less than one second to 30 seconds)
Mental and performance signs – Difficulty in ability to concentrate on tasks, inattention, compromised memory and recall, forgetting to communicate important information, and incorrectly performing tasks
Emotional and behavioral signs – Becoming uncharacteristically quiet, withdrawn or moody; low energy; and lacking motivation to perform work well

A low priority

NSF research shows that people in the United States get 20 percent less sleep than a century ago – mainly due to self-imposed sleep deprivation. Michael Breus, a clinical psychologist who specializes in sleep disorders, said one of the root causes of the U.S. “sleep epidemic” is the societal belief that sleep is not a priority. “If you are going to work more hours, you are going to spend less time on sleep – because you are not going to spend less time on family and friends,” Breus said.

A 2012 report from the Centers for Disease Control and Prevention found that in 2010, 30 percent of U.S. workers reported sleeping an average of less than six hours per night – less than the NSF-recommended seven to nine hours for adults. John Caldwell, a sleep, health and fatigue risk management consultant with Buffalo, WY-based Miller Ergonomics, believes the U.S. economy is partially at fault.

“Work hours have been steadily increasing over previous decades. As that occurs, you have less time to take care of family responsibilities, so where does that time come from? You then try and train yourself to sleep less every day,” Caldwell said.

Stress can be another factor for workers. “When they turn off the light and are lying in bed, it is really the first time they have had to themselves,” Breus said. “And all these thoughts just flood in and overtake them. It amps them up, and they are not going to fall asleep.”

The toll on the body

The decision to forgo sleep affects a person’s ability to perform work safely, Breus said, adding that the effects on motor skills and reaction time are most serious for jobs that involve heavy equipment. “For workers running a forklift, driving a truck, using heavy equipment, they are absolutely, positively going to be slower to react and not be able to perform with the acuity necessary to do whatever the job is,” he said.

Balkin described one of the most dangerous aspects of going to work sleep-deprived: Over a long period of time, workers become very limited in their ability to detect how sleepy they actually are.

“We are unable to cognitively remember what it felt like when we got enough sleep,” Balkin said. “This is how we get into cycles where we find it acceptable to get less than the recommended amount.”

Long-term cumulative sleep loss also affects a worker’s health, according to Michael Twery, director of the National Center on Sleep Disorders Research in the National Heart, Lung and Blood Institute’s Division of Lung Diseases at the National Institutes of Health. “The purpose of sleep is for each major internal system to recharge and realign; over time, if you prevent each system from doing what it needs to do, it can lead to issues with the bloodstream and hormone levels,” Twery said. This is directly related to serious health issues such as hypertension, obesity and diabetes, he added.

Can workers ‘catch up’ on sleep?

In a 2013 survey conducted by the Arlington, VA-based National Sleep Foundation, 56 percent of respondents reported sleeping more on weekends or non-workdays than on workdays. Among all respondents, U.S. adults averaged 7 hours and 22 minutes of sleep on those days versus an average of about six-and-a-half hours on workdays.

However, a recent study suggests that catch-up sleep may not make workers safer. In a study published online Oct. 1, 2013, in the American Journal of Physiology – Endocrinology and Metabolism, participants who slept six hours for six consecutive nights did not improve their performance on tests measuring their attention after they slept for 10 hours for three nights. Although participants reported feeling less stressed and sleepy after the three-day “weekend,” they were still affected by the long-term sleep deprivation, researchers concluded.

From the National Sleep Foundation's website: How much sleep is "enough"?

Encouraging better sleep among workers

Changing the societal perspectives on the importance of adequate sleep will take time, Caldwell said. “We still, as a culture, admire the guy who pulls the all-nighter and goes and works the next day or gets in his [vehicle] and drives halfway across the country,” he said. “We look at that person and go, ‘Wow, what a guy!’ This is despite the years of research that show this guy is just as dangerous on the highway, if not more so, as someone who is intoxicated.”

Employers should address sleep deprivation by educating workers on good sleep habits and including sleep patterns in wellness assessments, Caldwell said. Additionally, Twery recommends safety professionals encourage employees to see a medical professional if their sleep deprivation appears, or may become, serious.

Simply telling employees they need more sleep will have little impact, Breus said, unless the message can be made personal. For example, a worker could be made aware that he might not be able to spend as many years with his grandson because lack of sleep is damaging his health. “In terms of education, it has to be personal and at their level. It does not matter until it hits their hot button,” Breus said.

David Kuhlmann, medical director of the Sedalia, MO-based Bothwell Regional Health Center’s Bothwell Sleep Center, recommends safety and health professionals seriously consider establishing napping facilities in the workplace. He said employees could use the facilities after lunch or during a shift break to take a quick 10- to 15-minute nap. Naps have been proven to boost employee morale and efficiency, and will reduce the likelihood of workers abusing substances to help stay alert, Kuhlmann said.

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