Professor says cognitive impacts have health and safety consequences
Staff who regularly work hours that go against their natural body clock face significant damage to their ability to think and remember, a study has found.
A team of researchers, from Swansea University and Toulouse University, found a substantial decline in brain functions such as memory, speed of thought and wider cognitive ability among people who worked shifts.
The study tested brain functions of more than 3,200 employed and retired people in France. It revealed that the brain power of people who had worked a shift pattern rotating between mornings, afternoons, and nights for more than 10 years had the same results as someone six and a half years older who had never worked shifts.
Although the brain does deteriorate with age, the researchers said working out of time with the body’s circadian rhythms speeds up the process.
However, the study also showed that brains could recover cognitive ability after fives years of working normal daytime hours.
Previous research has already shown that working nights can have a negative impact on your physical health with incidents of ulcers, cardiovascular disease, metabolic syndrome, breast cancer, reproductive difficulties found more frequently in this group of workers.
Dr Philip Tucker, professor of psychology at Swansea University, said: “The study shows the long term effects of shift work on the body clock are not only harmful to workers’ physical health, but also affect their mental abilities. Such cognitive impairments may have consequences for the safety of shift workers and the society that they serve, as well as for shift workers’ quality of life.”
This is an observational study so no definitive conclusions can be drawn about cause and effect, but the disruption of the body clock could generate physiological stressors, which may in turn affect the functioning of the brain, researchers said.
The team also pointed to research that linked vitamin D deficiency, as a result of reduced exposure to daylight, to poorer cognition.
“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,” the team said in a statement.
'Chronical Effects of Shift Work On Cognition: Findings From The Visat Longitudinal Study' was published in the journal of Occupational & Environmental Medicine.