What do the Challenger disaster, the Chernobyl nuclear reactor meltdown and the Exxon Valdez oil spill all have in common? At least in part, these terrible accidents occurred because workers were sleep deprived.
Today's around the clock economy and the work schedules that go with it create new demands on workers that result in poor sleep and mistakes that can be very costly. Humans are clearly built to be awake about 16 hours a day and asleep about 8 hours a night. But what about night watchmen, emergency room nurses, firefighters, nuclear power plant operators and others who often are awake during the night performing demanding jobs that may have life or death consequences?
It has been estimated that about 20% of workers in industrialized countries have jobs that require shift work. According to the International Classification of Sleep Disorders, 2nd Ed., estimates suggest that between 2% and 5% of night shift workers have a clinically significant sleep disturbance and daytime drowsiness. It doesn't take a lot of math to calculate that hundreds of thousands to millions of workers may be suffering with sleep problems related to shift work. And these workers are often providing some of the most critical and important functions in our economy.
A major concern is that sleep deprivation may often be a consequence of shift work. This can lead to brief episodes of "micro-sleep" that may result in serious accidents or costly mistakes. In fact, catastrophic accidents are most likely to occur between 12:00 and 8:00 AM and between 1:00 and 3:00 PM. Note that these are the very times when we are most prone to sleep. The afternoon hours correspond to the circadian low that occurs after lunch. In some countries a siesta helps people get through this low period while in our high pressure, high performance society there is a tendency to work through it, exercise or drink coffee or energy drinks. A power nap is probably a more effective way of coping.
Another concern is that people working late shifts can develop a specific sleep problem known as Circadian Rhythm Sleep Disorder, Shift Work Type. This disorder is characterized by insomnia and excessive drowsiness. It can affect people working early morning, night, and rotating shifts.
Often shift workers are not getting enough sleep and the quality of the sleep they do get is not good. Impaired work performance and reduced alertness that leads to accidents are primary concerns. Quality of life outside of employment may be impacted, as decreased alertness and the need to sleep during the day can be socially problematic.
With night shift work it may be difficult to fall asleep when one gets home. Alertness may be reduced and sleepiness can occur during work hours. Naps during working hours may be needed or even occur unintentionally. A worker's sleep schedule may be further harmed by exposure to light at the wrong time of day, making it difficult for the circadian system to adapt. Driving home and then falling asleep under bright sunny conditions can be hard to do. An additional concern is that working the night shift may result in lasting changes in a person's sleep pattern such that Circadian Rhythm Sleep Disorder, Shift Work Type does not resolve- even after leaving the job and going to a daytime shift.
Added to the problems of reduced work performance, social problems with family and friends, and the danger of serious accidents and mistakes, are other difficulties associated with shift work disorder. These may include worsening of digestive and cardiovascular disorders, as well as possible drug and alcohol dependence due to efforts to stay awake at night and to improve sleep during the day.
Clearly, shift workers are important to the effective functioning of modern society- but the cost to these workers and to society as a whole can be great. In the next blog I will discuss some approaches to coping with shift work schedules. After all, a significant number of workers in the sleep field are technicians who stay up night after night to perform sleep studies!
