Man sleeping in bed

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

By Maja Jurisic, MD, VP, Medical Director National Accounts | 01/20/2017

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.

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%, 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. In the last 20 years, we have added 158 hours to our annual working and commuting time, the equivalent of a month of working hours. We live in a 24-hour society, where sleep is not valued, and four out of every ten of us are cutting back on sleep to gain time for other activities.

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. Even though 55% of American adults experience some type of sleep problem, less than 1% of the histories taken by doctors during routine exams even include a mention of sleep. Employers rarely think about their employees’ sleep habits when looking for ways to decrease the costs of medical care. Sleep also gets short shrift from the media when compared to the amount of attention given to diet and exercise in stories devoted to good health habits.

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 really should be regarded as an inherently unnatural act. The shift worker is in an unnatural temporal environment. Since shift workers make up 22% of the workforce, this means that at any given time, as many as 20 million sleep-deprived people are 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.

Since almost no one who works nights sticks to exactly the same sleep/wake times on days off, and it takes about a week for circadian realignment to occur each time someone shifts his/her sleep-wake cycle, 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 Shift Work

Working the night shift 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 shift work increases the risk of divorce by about 57%. Much of this is thought to be due to the domestic disruption caused by shift work. Three major spousal roles are affected—that of sexual partner, social companion, and protector-caregiver. Many of the marital problems spring from the shift worker’s inability to be there when needed at night, and the spouse left alone at home often experiences 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 meal times 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, 3rd 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 and don’t have time for a long nap is a “caff nap.” Since it takes caffeine about 30 minutes to take effect when we ingest it in a beverage, 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.

An Accident Waiting to Happen

Employers often do breath alcohol testing after an accident, but no one tests for sleep deprivation. 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%. 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%.

70-90% of industrial and transportation accidents are due to human error. 56% of shift workers fall asleep on the job at least once a week, and The Wall Street Journal reported that $70 billion is lost per year in productivity, accidents, and health costs as a result of workers’ inability to adjust to work schedules.


Although many of us are significantly sleep deprived, we remain ignorant of how much it affects our mood, performance and behavior. We think we’re doing just fine because we feel alert as long as we’re engaged in vigorous, interesting, challenging, and stimulating tasks. 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 strive to schedule shifts in ways that are least disruptive to human biology.

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


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