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Night shifts slow down workers' memory

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New research has revealed the long-term impact working night shifts has on the human body, with data suggesting those that work in the early hours have worse memories and slower mental speeds than those who work standard daytime hours.

The study, by academics from the Sigmund Freud Private University, Vienna, found that shift workers performed worse in five out of the six tests conducted – measuring everything from participants' processing speeds, working memory, alertness, impulse control and situational response.


Ways to help night workers:

Appropriate shift notice

Case study: Co-op's light experiment

The five Rs template


The study revealed shift workers performed particularly badly on tests measuring the mind's ability to process information.

A smaller – but still significant – impact was had on night workers' mental processing speed, memory skills, alertness and ability to filter out unimportant information. The only test where night workers and daytime workers performed the same, was in their ability to switch between different work tasks.

The results of the study add yet more weight to a growing conversation about the health impacts that night working causes on the UK’s estimated one-in-eight workers who work night shifts.

Previous research among NHS staff has already shown that 45% of women and 40% of men who do shift work have long-term illnesses compared with 39% and 36% respectively among those who work non-shift hours.

Commenting on the research, clinical therapist and sleep expert Suzie Sawyer told HR magazine: “While the authors acknowledge further studies are needed to better understand why this is the case, we have long known from research that going against the body’s natural circadian rhythm can cause other health issues, especially for women with hormonal disruption.

“The body naturally fulfils many important functions during the night, specifically liver detoxification, and post absorptive digestion to assimilate nutrients. These processes will be impaired if the body is not resting.”

One of the worst sectors for sleep deprivation is the haulage industry. It is 100,000 drivers short, and its image of consisting of long, overnight hours has been blamed for putting off younger people.

According to the Road Haulage Association, undiagnosed sleep disorders are rife among drivers, and they can cause more impairment than being over the drink-drive limit.

Last year the association was critical of government moves to actually extend drivers’ hours in response to the truck driver shortage.

Data from Hult International Business School suggests the UK loses 200,000 working days to absenteeism due to lack of sleep.

Think tank Rand Europe has also found that employees who sleep less than six hours a night lose around six more working days through absenteeism or presenteeism each year than those who sleep seven to nine hours a night.