The effects of shift work on brain function


Tired, overworked doc

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Anyone who has worked as a police officer, firefighter, cab driver or nurse knows about the debilitating physical effects of shift work. As if the sheer antisocial nature of shift work hours weren’t enough to give us pause, WebMD notes that the long-term effects resulting from a disturbance in your natural circadian rhythm can be far more serious.

Along with chronic exhaustion, conditions such as obesity, heart disease, diabetes, ulcers and certain types of cancer have all been linked to the constant interruption to the body clock that routine shift work brings. Indeed, until recently, the majority of research done into the effects of shift work has concentrated on the physiological damage we might do to ourselves to earn a crust.

Now a European study published in Occupational & Environmental Medicine has given some scientific insight into the effects on workers’ mental abilities.


This is your brain on yawns

Throughout a period of 10 years, a team led by Dr. Jean-Claude Marquié of the University of Toulouse studied 3,232 employed and retired workers who, when the study began, were ages 32, 42, 52 and 62. Just under half of the people taking part had “shift work experience” — of at least 50 days in a year — while the rest had none. The workers were tested by the researchers at the beginning of the study, after five years and after the 10-year mark. At each point, the team assessed the workers’ reaction times and memory capabilities.

They discovered that those who were working a rotating shift pattern or had done so for 10 or more years registered markedly “lower cognitive and global memory scores” than those who had regularly worked traditional office hours. In fact, the deterioration experienced by the shift workers was equivalent to 6.5 years of aging.

When the team looked at whether the deterioration was reversible, they found that recovery from the psychological effects of shift work took at least five years.


Safety first

It’s important to remember that this is an “observational study.” It does not conclusively prove that the sleep disruption brought about by shift work is the only factor to consider. Research elsewhere has found links between vitamin D deficiency and cognitive ability — the very sleepy docsame vitamin D that we obtain from sunlight during the day. However, the team says it is important to determine the “physiological stressors” that are a result of shift work that might also affect the brain.

When you consider that a Bureau of Labor Statistics study found that “almost 15 million Americans work full time on evening shift, night shift, rotating shifts or other employer arranged irregular schedules,” that’s an alarming number of people who are potentially having to put their health in jeopardy.

Of course, aside from long-term psychological effects, slower reaction times and impaired memory can put the individual shift worker in immediate danger. Operating vehicles and other machinery when tired is just one of the numerous dangers shift workers can face.

The effects of poor concentration are potentially dangerous for others, too. The team says its results “may have important safety consequences not only for the individuals concerned, but also for society as a whole, given the increasing number of jobs in high hazard situations that are performed at night.” Disasters such as the Exxon Valdez oil spill, Chernobyl and Three Mile Island have all been linked to fatigue brought about by shift work.

The solution to all this isn’t easy. Work is, after all, work. And according to the National Sleep Foundation “treatment for shift work sleep disorder is limited.” They advise adopting a regular sleep pattern (even if it isn’t normal hours), keeping your brain and body active while at work (go on, War and Peace isn’t going to read itself, or you could become a Candy Crush champ —your call), and — best of all — power napping. If you ask us, that’s a useful tool in any crisis.