Shift Work May Impact Cognitive Performance

A new study suggests shift workers may experience some degree of cognitive impairment.

Although the limitations resolve after ending shift work, it may take up to five years for this to occur, say researchers.

Investigators from Uppsala University in Sweden found that compared to non-shift workers, shift workers needed more time to complete a test that is frequently used by physicians to screen for cognitive impairment.

However, those who had quit shift work more than five years ago completed the test just as quick as the non-shift workers.

The findings appear in the journal Neurobiology of Aging.

Researchers reviewed data from around 7000 individuals participating in the Swedish cohort study EpiHealth. They sought to examine whether shift work history would be linked to performance.

To do this, they used a test called the “Trail Making Test,” which consists of two parts. Part A requires participants to connect circles labeled with numbers one to 25 in an ascending order. In part B, participants must alternate between numbers and letters in an ascending order.

The time to complete these tests has been shown to increase with age.

“Our results indicate that shift work is linked to poorer performance on a test that is frequently used to screen for cognitive impairment in humans,” said Dr. Christian Benedict, associate professor at the Department of Neuroscience at Uppsala University and corresponding author of the study.

“The poorer performance was only observed in current shift workers and those who worked shifts during the past five years. In contrast, no difference was observed between non-shift workers and those who had quit shift work more than five years ago.

The latter could suggest that it may take at least five years for previous shift workers to recover brain functions that are relevant to the performance on this test,” Christian Benedict said.

Source: Uppsala University