How Dangerous is the Night Shift?

In a modern world with 24-hour service becoming increasingly expected from a wide range of businesses around the world, what kind of pressure does this place on people doing shift work when most people are still asleep?   In a recent article published in the British Medical Journal,  a team of  Canadian and Norwegian medical researchers looked at thirty-four previous studies examining the medical and psychological effects of shift work on over two million workers.   Based on their meta-analysis, the researchers found that shift work was associated with increased risk of myocardial infarction (risk ratio 1.23, 95% confidence interval 1.15 to 1.31; I(2)=0) and ischaemic stroke (1.05, 1.01 to 1.09; I(2)=0).  There was also an increased risk of coronary events although this varied widely across studies.   Overall, the study reviewed information on 6598 myocardial infarctions, 17 359 coronary events, and 1854 ischaemic strokes occurring in shift workers.   Given that 32% of workers in Canada alone are shift workers, the potential health costs for society as a whole are immense.  Although overall mortality was no greater for shift workers than in the general population, shift workers are prone to increased risk of problems with poor sleep, high blood pressure, and other related health problems.  The researchers carefully examined socioeconomic status and smoking in their study and ruled them out as contributing factors.

According to University of Western Ontario researcher D.G. Hackam, one of the authors of the study,  "night shift workers are up all the time and they don't have a defined rest period. They are in a state of perpetual nervous system activation which is bad for things like obesity and cholesterol."    To prevent potential health problems, the study authors suggest that prospective shift workers could be screened for high-risk factors such as hypertension and high cholesterol.  Shift workers could also be educated about lifestyle factors that could contribute to medical problems including disrupted sleep patterns, eating habits, domestic and emotional issues, psychological isolation, and dependence on chemical stimulants or sedatives.  

Disturbed sleep and related problems can also mean that shift workers are more prone to impaired judgment and increased likelihood of work-related errors.  To prevent problems associated with shift work,  health authorities recommend limiting night shifts to no more than twelve hours at a time and ensuring a minimum of two full nights of sleep between day and night shifts.  Since work safety regulations controlling the use of shift work is limited in many jurisdictions however, the health problems associated with shiftwork are likely to continue.

Which might be something to consider when you're arguing with that night clerk at 4 am over receiving the correct change...

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Comments

[Pat G]

? Shift workers could also be educated about lifestyle factors that could contribute to medical problems including disrupted sleep patterns, eating habits, domestic and emotional issues, psychological isolation, and dependence on chemical stimulants or sedatives.??

As a shift worker I have to ask if you are joking about that? It reminds me of the story of a research project to find out why some poor cannot keep a job; when the researches discovered that most of them did not have the money for alarm clocks the researches offered to stop the study and use the research money to buy every subject/participant an alarm clock. Unfortunately they were not permitted to solve the problem that way because that would invalidate the research and would also interfere with the free market.

I, and all my co-workers are well educated (virtually everyone has a BA/BSC etc and some have MAs,) already about disrupted sleep patterns but we can't do anything much to prevent it. We are similarly well aware of nutrition and psychological and social isolation but again there is litte we can do to avoid these problems.

I know a fair bit about health and cardiac problems and food choices but when I am working I deliberately choose dense calories because I do not have enough time to chew my food properly so salads are not an option and since I cannot eat when I am hungry I almost always have to eat when I am not hungry or eat dense calories now to keep me going through a too long stretch when I cannot eat. The same kind of inability to control these variables affects sleep and all the other factors mentioned. I am stressed to the breaking point but cannot stop.

I am annoyed and offended and urge you to re-think your research. At the same time you might be better off figuring out how to change the current paradigm which turns human beings into borgs in service of the corporate model. Hopefully, peak oil and a financial crash may free us wage slaves before I have a second heart attack.

[Romeo Vitelli]

I'm simply reporting on existing research. Perhaps you can contact the authors directly to express your concerns.

[Ana]

To Pat G. You should not criticize the scientists who have brought to light the significant health consequences caused by shift work and the suggested actions that may help minimize shift work's detrimental effects. Many (and I would probably even say most) shift workers may not realize that many of their health complaints are a direct result of shift work, and that lifestyle change can help. Your inability to follow positive lifestyle changes is not a fault of the scientists but of your work environment.

The more these consequences and effects on health are documented and the information realized by workers, policy makers and industry, the more pressure corporations will receive to change their business practices. In fact, in Europe, class action suits have been filed against corporations regarding the negative effects of shift work, and change is slowly in progress.

Anger and frustration should be directed at policy makers and corporations and not the scientists who are analyzing and reporting the effects on the community.