A shifting work schedule leads to a number of health issues such as heart diseases, metabolic syndrome, peptic ulcer, and cancer, among others. The body's disrupted circadian clock causes the said health problems, and it is also this disturbed sleeping patterns that damage the brain. Chronic shift work, therefore, doesn't only have negative effects to the body; it can also cause deterioration in the functioning of the brain, according to a recent study.

The research published in Occupational & Environmental Medicine studied the cognitive skills of over 3,000 people living in France, half of whom had experience working shifts.

Results showed that those who were currently or who had previously worked shifts had lower scores on memory, processing speed, and overall brain function compared to those who had only worked normal office hours.

Also those who've worked shifting schedules for 10 or more years had lower global cognitive and memory scores, which is equivalent to 6.5 years of age-related cognitive decline, compared to those who worked normal office hours, the study found.

The impact was stronger after a period of 10 or more years of such a work pattern - and seen to be much greater for those working a rotating shift pattern

Good news on the study, according to the researchers, was the possibility to restore normal cognitive functions after five years of no shift work.

For the reason of such mental deterioration, the study authors said the study was observational, and wouldn't be able to determine which caused the cognitive decline.

Co-author Dr. Philip Tucker and senior lecturer in the psychology department at Swansea University in the U.K., said "If it's not sleep, the strongest candidate would be destruction of circadian rhythms."

Shift workers, who sleep during the day, may also have a vitamin D deficiency, but the disruption of circadian rhythms is still the main contender, the researchers said.

"You could argue that if you start messing about with those clocks, there's going to be all sorts of effects," Tucker said

"The cognitive impairment observed in the present study 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," according to the study authors.

While shift workers might not be able to choose their work schedule due to office protocols, there are possible interventions that could be done, such as taking periodic breaks at work, taking 20-minute naps to rejuvenate the mind and the body, getting some physical exercises, and engaging in mental activities such as reading and solving crossword puzzles to fight cognitive decline even while working on chronic shifts.