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Shift work could speed up brain decline

02/12/2014 | By Freedom Health Insurance
A new study, published in the Occupational and Environmental Medicine journal, shows that working antisocial hours for long periods of time (10 or more years) can prematurely age the brain by more than 6 years compared to the normal brain decline associated with age (1).

The study tracked and tested the cognitive abilities of over 3,000 participants 3 times over a 10 year period. Medical News Today commented that the study found that people who worked, or who were currently working, in shifts scored lower than those working normal hours in tests concerning memory, processing speed and overall brain power (2).

Reporting on this study, BBC News Health tells us that whilst the brain naturally declines with our age, working shifts, especially when these affect our body’s internal clock (which tells us to be active in the day and asleep at night), can speed this up (3).

The good news is that this process may be reversible. The study showed that people who stopped working shifts recovered their lost mental function after at least 5 years. However, BBC News Health goes on to say that Prof Derk-Jan Dijk from the Surrey Sleep Centre has warned that lower sleep quality is still an issue for retired shift workers compared to people who had never worked nights.

Medical News Today also reports that the study is only an observational one and conclusive proof for the direct link between shifts and cognitive decline cannot be provided; however, researchers believe that the manner in which shift work can disrupt the body’s circadian rhythms could generate psychological stressors, impacting the brain’s functions.

The findings add to a body of research about how shift work damages health. Previous studies have shown that night shifts could double the risk of breast cancer (4), while cancer, depression, diabetes, obesity and strokes have also been linked to poor sleeping habits (5). The NHS Choices website suggests that other lifestyle factors may contribute to the risks though and these could be offset with regular exercise, moderate alcohol intake and a balanced diet.

The scientists concluded that all of these findings should raise some alarm signals, not only for individuals but also for society, pointing out "the increasing number of jobs in high hazard situations that are performed at night" (6). 

Useful Pages
1. Marquie, J.C., et al, 2014. Chronic effects of shift work on cognition: findings from the VISAT longitudinal study, Occupation and Environmental Medicine Journal, 3rd November. Available here.
2. McIntosh, J., 2014. Could shift work impair brain functioning?, Medical News Today, 4th November. Available here.
3. Gallagher, J., 2014. Shift work dulls your brain – report, BBC News, 4th November. Available here.
4. NHS Choices, 2013. Long-term night shifts can ‘double’ breast cancer risk. 2nd July. Available here.
5. Davies, M., 2014. Long-term shift work ages the brain: More than a decade ‘knocks six years off memory and thinking skills’, Daily Mail. 4th November. Available here.
6. AFP, 2014. Shift work link to brain power decline: study, Yahoo News, 3rd November. Available here.