Study Shows How Working Nights Impacts Your Brain Health

A new study has found that middle-aged and older adults who work late or overnight shifts have a 79 percent higher rate of cognitive impairment than those who work traditional hours

The trial’s results were published yesterday in Plos One. Researchers at Canada’s York University analyzed data of 47,811 older adults (aged 45–85) from the Canadian Longitudinal Study on Aging. Included were details of their employment history and schedules, as well as results of their cognitive function tests.

One in five participants had been exposed to so-called “shift work” during their careers. Shift work refers to any schedule that falls outside of the 9 am to 5 pm timeframe. Shift workers include bartenders, construction workers, airline pilots, doctors, and nurses. Those who had done shift work had rates of cognitive impairment 79 percent higher than people who worked only during the day. Participants who had worked night shifts during their longest-held job had rates 53 percent higher.

The report’s authors believe a disruption to circadian rhythm is to blame. “The 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.”

This isn’t the first report to link late shifts with health problems. A 2021 study of 283,657 people found that those working nights are at an elevated risk of developing a condition known as atrial fibrillation, which causes an abnormally fast heartbeat. Shift workers in positions for 10 years or less had an increased risk of 12 percent, while risk for those working nights for a decade or more increased to 18 percent.