Effects of Shift Work: The Danger of Not Getting Enough Sleep

Maja Jurisic, MD, VP, Medical Director National Accounts

Despite popular perception, sleep is not a luxury—it is a necessity. More than 100 million Americans are sleep-deprived and make crucial business and personal decisions in an impaired state. The cost of skimping on sleep is steep and estimated to be in the realm of $150 billion a year in terms of productivity and accidents.

In 2020, the National Sleep Foundation’s (NSF) annual poll showed that Americans felt “sleepy” on average three times a week during what should be their waking hours.  The primary response for 62 percent of them was to try to “shake it off.”

Before Thomas Edison invented the electric light in 1879, most people slept 10 hours each night. Over the next century we gradually reduced our nightly sleep by 20 percent, to eight hours per night. More recent studies indicate that Americans now average seven hours per night, and one third of the population is sleeping less than 6 hours each night. We live in a 24-hour society, where sleep is not valued, and many are cutting back on sleep to gain time for other activities.  Adding to that, in 2020, the NSF reported that 55 percent of people who had enough time to sleep were not getting restorative sleep, and did not wake up feeling refreshed, alert and able to be fully productive throughout their waking hours.

Although sleep is part of the triad of wellness (along with exercise and nutrition), talking about sleep is not part of the routine conversation between physician and patient. Employers rarely think about their employees’ sleep habits when looking for ways to decrease the costs of medical care.  Yet, Matthew Walker, Director of UC Berkeley’s Sleep and Neuroimaging Lab, writes in his book Why We Sleep, “In the context of injury, there is no better risk-mitigating insurance police…than sleep.”

Shift Work

Night shifts date back to the early days of seafaring, although Henry Ford sometimes gets blamed as the father of shift-work sleep disorders because his assembly lines made it economically feasible for factories to run all night. Working the night shift takes a big toll, because being up at night and sleeping during the day is contrary to human biology.

Some people cope well working at night, most do not. Since we are biologically hard-wired to be active during the day and sleepy at night, working at night should be regarded as an inherently unnatural act. The shift worker is in an unnatural temporal environment.  The US Bureau of Labor Statistics notes that 18-26 percent of the adult population are shift workers, manning some of our most important jobs in law enforcement, firefighting, healthcare, power generation, manufacturing, and transportation.

Night workers typically get two hours less sleep than daytime workers, about 10 hours less per week, according to surveys in the United States and Europe. Moreover, the sleep they do get tends to be less restful. Sleep becomes the major preoccupation for many night workers.

It takes about a week for circadian realignment to occur each time someone shifts his/her sleep-wake cycle.  Since almost no one who works nights sticks to the same sleep/wake times on days off, most night shift workers’ bodies never become fully adjusted to any single schedule. During the process of realignment, their sense of well-being, their mood, and performance efficiency are all negatively affected. 40 seems to be a threshold age, after which it takes even longer to make adjustments in circadian rhythms.

Negative Effects of Night Shift Work

Working the graveyard shift (11 p.m. -7 a.m.) can lead to digestive problems, a higher incidence of cardiovascular disease, higher cholesterol, increased depression and anxiety disorders, more errors and accidents, and a higher rate of divorce.

A longitudinal study showed that night shift work increases the risk of divorce by about 57 percent. Much of this is thought to be due to the domestic disruption caused by shift work.  Many marital problems can spring from the shift worker’s inability to be there when needed at night, and the spouse left alone at home can experience feelings of loneliness and insecurity.

The evening shift, which doesn’t have much impact on sleep, does still have a crushing impact on the role of the shift worker as social companion, as well as on that worker’s family role of parent.

Solutions to the Problems of Shift Work Include:

  • Rotating shifts clockwise. It is easier for our bodies to adjust our circadian rhythms going from day to evening to night shifts than the other way around
  • Maintaining a regular sleep schedule, even on days off
  • Keeping mealtimes the same each day
  • Staying fit and moving around during short breaks throughout the shift
  • Avoiding overuse of caffeine, especially towards the end of a night shift
  • Not leaving the most tedious tasks for the end of the shift, when you’re most likely to be tired, and least likely to stay alert
  • Using naps strategically prior to work. Since a 45-minute nap can improve alertness for 6 hours, third shift workers can take a nap prior to starting their shift. Another option to help with alertness when we are trying to overcome our biology is a “caff nap.”  It takes caffeine about 30 minutes to take effect when we drink it, so, drinking a beverage with caffeine prior to taking a 20-minute nap can be useful. The caffeine “kicks in” right about the time the napper is getting up.

A survey of 1469 shift workers in 2021 showed that schedule transparency and flexibility was very important to them.  The top priority for 65 percent was getting advanced notice of schedules, so they could better plan their lives.  96 percent agreed that shift workers deserve “more respect” and recognition of the importance of their work.

An Accident Waiting to Happen

Australian researchers found that after 17 hours of being awake, a group of sleep-deprived volunteers had the same scores on performance tests as drinking volunteers who had blood alcohol levels of 0.05 percent. After 24 hours of being awake, the sleep-deprived group had the same coordination deficits as those with a blood alcohol level of 0.1 percent.

It was noted that 56 percent of shift workers fall asleep on the job at least once a week, and 70-90 percent of industrial and transportation accidents are due to human error.


Although many of us are significantly sleep deprived, we remain unaware of how much it affects our mood, performance, and behavior. We readily excuse any drowsiness we feel after a heavy lunch, or if we’re in a warm room, or listening to a dull lecture: we attribute our sleepiness to these “causes” and not to an underlying sleep debt.

The difference between a rich, vital, healthy life, and a diminished one, may be as little as an extra 30 minutes of sleep every night. In the long run, shortchanging sleep depletes our mental acuity and undermines our potential for sustained achievement.

Well-slept people are more engaged, can keep more ideas in their head simultaneously, and can think through new ideas more clearly.

Employers who want the best for their employees, and the best from their employees, should help them understand the importance of sleep for their well-being, provide them with information to make good lifestyle choices when it comes to sleep, and schedule shifts in ways that are least disruptive to human biology.

For more information on maintaining a healthy workforce, contact a Concentra representative.


  1. Principles & Practice of Sleep Medicine, Meir H. Kryger MD, Thomas Roth PhD, William C. Dement MD PhD, 2010.
  2. The Promise of Sleep, William C. Dement, Christopher Vaughan, 2000.
  3. A Good Night’s Sleep, The Harvard Medical School Guide, Lawrence Epstein, 2006.
  4. Power Sleep, James B. Maas, 1998.
  5. The National Sleep Foundation website.