March 8 (UPI) — Night-shift work can cause memory and other brain function problems, an analysis published Tuesday by the journal Occupational and Environmental Medicine found.
It is also associated with lower levels of alertness and visual focus, as well as declines in the ability to control impulses and situational response, the researchers said.
This could potentially raise the risk for workplace injuries and errors, they said.
Based on data from 18 studies that collectively included more than 18,000 participants, researchers found that night-shift workers had lower scores on tests designed to measure impulse control and situational response, or decision-making ability.
Night-shift workers also scored slightly lower on tests assessing brain processing speed, working memory, alertness and ability to filter out unimportant visual clues, the data showed.
“Our findings suggest an association between shift work and decreased cognitive functions such as working memory,” study co-author Thomas Vlasak told UPI in an email.
This “may ultimately contribute to work-related injuries and errors leading to potential implications for occupational health and safety especially for high-risk and safety-sensitive professions,” said Vlasak, a member of the scientific staff at Sigmund Freud Private University in Linz, Austria.
Previous studies have linked shift work with sleep problems and other serious health complications, including heart disease, obesity, diabetes, mood disorders and substance abuse.
Working outside the normal day-night cycle interferes with the body’s internal clock, or circadian rhythm, because it results in affected people sleeping “out of step” with the normal light-dark cycle, Vlasak and his colleagues said.
Interference with the circadian rhythm affects production of the hormones that govern it, such as cortisol and melatonin, which impacts stress response and mental and physical health, they said.
For this analysis, the Austrian researchers reviewed data from 18 studies published between 2005 and 2020 that collectively enrolled 18,802 working adults who had an average age of 35.
Five of the studies compared workers in fixed shifts with those working normal office hours, while 11 compared workers in rotating shifts with those working normal office hours and two did not specify shift type.
Half of the studies included healthcare professionals while the other half focused on different professions, such as police officers.
Based on the findings, companies who engage shift-workers should consider protective countermeasures such as scheduled naps, recovery plans and regular employee monitoring to minimize potential health effects, the researchers said.
“Studies suggest that managing healthy sleep patterns outside of shift work, taking naps when working overnight, following a healthy diet and controlled exposure to light during and after work can help to minimize risks,” Vlasak said.