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• Posted May 14, 2024

Science Shows How Night Shifts Help Bring on Disease

Night shift work can increase a person's risk of chronic disease, and a new study reveals one possible explanation for this.

It appears that just a few days on a night shift schedule throws off body rhythms tied to regulation of blood sugar, energy burning and inflammation, researchers found.

"There are processes tied to the master biological clock in our brain that are saying that day is day and night is night and other processes that follow rhythms set elsewhere in the body that say night is day and day is night,"explained senior study author Hans Van Dongen, director of the Sleep and Performance Research Center at Washington State University.

"When internal rhythms are dysregulated, you have this enduring stress in your system that we believe has long-term health consequences,"Van Dongen said in a university news release.

Night shift workers have a higher risk of serious health problems like heart attack, diabetes, metabolic syndrome and cancer, Harvard Medical School says.

For the study, researchers performed a controlled laboratory experiment involving volunteers who were put on simulated night or day shift schedules for three days.

Following their last shift, the participants were kept awake for 24 hours under constant conditions to measure their internal biological rhythms, researchers said.

Blood samples drawn during the 24-hour period revealed proteins present in immune cells closely tied to the master biological clock that keeps the body on a 24-hour rhythm, researchers said.

The master clock is resilient to altered shift schedules, so those protein rhythms didn't change much in response to the night shift schedule.

However, many other proteins had rhythms that changed substantially in night shift workers, researchers found.

There was a nearly complete reversal in the rhythms of proteins that manage blood sugar, researchers found.

In addition, the processes involved in insulin production and sensitivity were no longer synchronized in night shift workers.

This effect might be happening because the body is trying to undo blood sugar changes triggered by a night shift schedule, researchers said.

It might be a healthy response in the moment, but over time poorly regulated blood sugar levels can damage cells and organs.

The researchers next plan to study real-world workers, to see if the results of their lab experiment occur during regular night shift work.

The new study was published recently in the Journal of Proteome Research.

More information

Harvard Medical School has more on night shift work and health.

SOURCE: Washington State University, news release, May 9, 2024