It's not just a tired body that needs rest. The brain also relies on a solid sleep cycle for optimum health and longevity. But, as new research points out, shift work can disrupt the internal clock and weaken brain power over time. One new study suggests a decade of shift work can age the brain by more than six additional years.
Late night, antisocial hours on the job have previously been linked to a litany of health problems, including ulcers, cardiovascular disease, metabolic syndrome and even some cancers. But the latest study, carried out by researchers at the University of Swansea and the University of Toulouse, found the consistent disruption of a person's internal clock also diminished the brain's processing speed and memory abilities.
The researchers arrived at their findings after having thousands of patients in the United Kingdom and France perform tests in memory, fast-thinking and general cognitive ability. The scores of test-takers who had spent a decade or more working shifts -- night work or shifts that alternated but included regular nighttime work -- were on par with non-shift-workers who were 6.5 years older.
Researchers were able to track test-takers over time, and confirmed that additional shift work seemed to increasingly dull the brain.
"It was quite a substantial decline in brain function," Philip Tucker, one of the study's researchers, told the BBC. "It is likely that when people trying to undertake complex cognitive tasks then they might make more mistakes and slip-ups, maybe one in 100 makes a mistake with a very large consequence, but it's hard to say how big a difference it would make in day-to-day life."
The study wasn't all doom and gloom. Though researchers called shift work a "necessary evil," they did find that brain function normalized after five years off the job.
"The reversibility is a really exciting finding because no-one else has shown it and no matter how compromised a person may be there's always hope of recovery," Michael Hastings, a scientist with United Kingdom's Medical Research Council's Laboratory of Molecular Biology, told the BBC.
But for many, finding a different job isn't an option. That's why Tucker and his colleagues recommend more stringent health monitoring of those who work odd hours.
"The current findings highlight the importance of maintaining a medical surveillance of shift workers, especially of those who have remained in shift work for 10 years or more," the researchers concluded in their study.
The research paper was published Monday in the journal Occupational and Environmental Medicine.