• Posted April 10, 2025

Eating By Day Might Cut Heart Health Risk To Night Shift Workers

Night shift workers might be able to protect their heart health by only eating during daylight hours, a new study says.

Participants in an experiment experienced fewer heart health risk factors if they only ate during the daytime while working a night shift, researchers reported April 8 in the journal Nature Communications.

“Our study controlled for every factor that you could imagine that could affect the results, so we can say that it’s the food timing effect that is driving these changes in the cardiovascular risk factors,” lead researcher Dr. Sarah Chellappa, an associate professor at the University of Southampton in the U.K., said in a news release.

Numerous studies have linked night shift work to a number of serious health risks, including risk to heart health, researchers said in background notes.

“Our prior research has shown that circadian misalignment – the mistiming of our behavioral cycle relative to our internal body clock – increases cardiovascular risk factors,” senior researcher Frank Scheer, director of the Medical Chronobiology Program at Brigham and Women’s Hospital in Boston, said in a news release.

“We wanted to understand what can be done to lower this risk, and our new research suggests food timing could be that target,” Scheer added.

Prior animal studies showed that aligning food timing with the internal body clock might mitigate the health risks of staying awake through the nighttime, researchers said.

To test this, researchers asked 20 healthy young people to participate in a two-week sleep lab study at the Brigham and Women’s Center for Clinical Investigation.

Participants had no access to windows, watches or electronics that would clue them in to the actual time. They stayed awake for 32 hours in a dimly lit environment to shake up their body clocks, and then participated in simulated night shift work.

During this experiment, some participants were randomly assigned to eat only during the daytime, while the rest were allowed to eat during the night as most shift workers do.

All the workers had an identical schedule of naps to eliminate any differences due to sleep schedule, researchers added.

Results showed that people had increases in heart risk factors after their simulated night shifts, but only among those who could eat whenever they liked. 

Heart risk factors remained the same among participants who only ate during the daytime, even though their diet did not differ from that of those allowed to eat at night, researchers said.

Larger-scale studies are needed to confirm and better understand this effect, but the researchers said the results are “promising.”

“These findings indicate that daytime eating, despite mistimed sleep, may mitigate changes in cardiovascular risk factors and offer translational evidence for developing a behavioral strategy to help minimize the adverse changes in cardiovascular risk factors in individuals exposed to circadian misalignment, such as shift workers,” researchers concluded in their paper.

More information

Harvard Medical School has more on the health effects of shift work.

SOURCES: Nature Communications, April 8, 2025; Mass General Brigham, news release, April 8, 2025