TORONTO, Ontario — Shift work — or working late into the night or overnight hours — could end up impairing memory and cognition in middle-aged or older workers. The research looked at nearly 50,000 adults who worked outside the normal 9 a.m. to 5 p.m. day.
Researchers from York University in Canada found that those who worked night shifts or rotational shifts were affected the most. The study authors used data from the Canadian Longitudinal Study on Aging to reach their conclusions, published in the journal PLoS ONE.
The 47,811 participants included self-reported information on their employment and work schedules alongside their results from cognitive function tests. One in every five workers (21%) reported doing some kind of shift work during their career.
Higher rates of cognitive impairment were found among participants who reported working more night shifts during their current job or night shift work during their longest-tenured job. Night shift work also had an association with memory function impairment, and rotating shift work had a link to impairment of executive function.
“The study findings suggest a potential link between shift work exposure and cognitive function impairment. We speculate that disruptive circadian stimuli may play a role in neurodegeneration contributing to cognitive impairment; however, additional studies are needed to confirm the association between shiftwork and cognitive impairment as well as any physiological pathways that underlie the mechanism,” the study authors conclude in a media release.
Shift work can lead to significant health impacts
A 2023 study warns that just four weeks of shift work could disrupt women’s biological clocks and negatively impact their fertility. Study authors explained that shift work can interfere with the body’s circadian rhythm, which is the physical, mental, and behavioral changes that follow a 24-hour cycle in response to light variations.
These internal clocks regulate numerous biological functions and processes, such as the sleep cycle, digestion, hormone flow, and reproduction. However, they can be easily disrupted by inappropriate light exposure, such as exposure to light at night.
In 2021, researchers pinpointed the likely reason for the increase in cancer risk of people who regularly work night shifts. The study by scientists at Washington State University’s Health Sciences sleep laboratory showed that the normal 24-hour rhythm is disrupted in those who regularly worked at night. This causes abnormal activity of certain genes associated with cancer, increasing the risk of DNA damage.
South West News Service writer Jim Leffman contributed to this report.