NSC Labor Division news Fatigue Research/studies Shift work

Study links shift work to cognitive issues

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Linz, Austria — Shift work may be associated with poorer memory and slower mental processing speed, as well as lower levels of alertness and visual focus, results of a recent study out of Austria suggest.

Researchers analyzed data from 18 studies involving nearly 19,000 participants who completed tests that allowed for the assessment of six cognitive functions: processing speed, working memory, impulse control and situational response, alertness, visual attention, and task switching. Half of the studies focused on health care professionals while the other half involved various other professions.

Shift workers performed “significantly worse” in five of the cognitive functions, the researchers concluded. “A large significant effect was seen for impulse control and situational response,” according to a BMJ Publishing Group press release. Meanwhile, significant but smaller effects were seen in processing speed, memory, alertness and visual attention. No effect on task switching was observed.

Previous research has linked shift work to serious health issues such as sleep disorders, cardiovascular disease, obesity and diabetes. The reason often cited for issues stemming from shift work is the internal body clock, or circadian rhythms, being out of line with the normal cycle of light and darkness. This can disrupt hormones, such as melatonin and cortisol, that govern sleeping and waking in the body.


The researchers recommend “protective countermeasures,” including naps, recovery plans and regular monitoring for alertness/attention issues. In addition, they warn that, because of different demands and workloads of certain jobs, the impact of shift work might be underestimated for certain professions.

“When a more consistent body of high-quality literature is available, we highly recommend replication of analysis to develop practical interventions to overcome neurobehavioral impairment,” the researchers write.

The study was published online in the journal Occupational & Environmental Medicine.

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