Eating only during the day protects people from the heart risks of shift work

A study led by researchers at Mass General Brigham suggests that when it comes to cardiovascular health, food timing can be a greater risk factor than sleep timing.

Many studies have shown that working night shifts is associated with serious health risks, including the heart. However, a new study from the popular general Brigham suggests that eating only during the day could help people avoid the health risks associated with shift work. The results are published in Natural communication.

“Our previous studies have shown that circadian inconsistencies (mistakes in behavioral cycles relative to the internal body clock) increase cardiovascular risk factors,” said the senior author of the author. Frank AJL Scheer, PhDprofessor and director of medicine. Medical Chronicles Program He is a founding member of the Mass General Brigham Healthcare System at Brigham and Women’s Hospital. “We wanted to understand what we could do to reduce this risk. Our new research suggests that food timing could be the target.”

Animal studies have shown that timing foods with internal internal clocks can reduce the health risks of staying awake during typical breaks, leading Sher and his colleagues to test this concept in humans.

For this study, the researchers participated in a two-week patient study of patients at the Brigham and Women’s Clinical Research Center. They had no access to windows, clocks or electronics. The effect of circadian inconsistencies can be determined by comparing how their physical function changes from before and after simulated nighttime work.

Study participants followed a “constant routine protocol,” a controlled laboratory setup that could tear the effects of circadian rhythms from the environment and behavior (sleep/wake, bright/dark patterns, etc.). During this protocol, participants woke up in a dimly lit environment for 32 hours, maintained a constant physical posture and ate the same snack every hour. They then participated in simulated nightworks and were assigned to meals during the night (as most night workers do) or only during the day. Finally, participants tested the later phases of the simulated nightwork according to another constant routine protocol. Importantly, both groups had the same schedule of nap time, and therefore differences between groups were not due to differences in sleep schedules.

Investigators examined the later stages of food timing for participants’ cardiovascular risk factors and how it changed after simulated nighttime work. Researchers measured a variety of cardiovascular risk factors, including autonomic nervous system markers, plasminogen activator inhibitor-1 (increasing the risk of thrombosis), and blood pressure.

Surprisingly, these cardiovascular risk factors increased after simulating nighttime work compared to baselines for participants scheduled to eat day and night. However, risk factors did not differ between groups in how much money and what they ate, but remained the same in study participants who only ate during the day. when They ate.

Limitations to this study include small sample sizes, but typical sizes for such highly controlled, intensive, randomized controlled trials. Furthermore, this study lasted for two weeks and may not reflect the chronic risk of nighttime and daytime diets.

The strength was that the study participants had very close control over their sleep, diet, light exposure, physical posture, and activity schedules.

“Our study controlled for any factors that could be imagined to have an impact on outcomes, so we can say that it is the food timing effect that drives these changes in cardiovascular risk factors.”

Although further research is needed to show the long-term health effects of daytime and nighttime diets, the results are “promising” and suggest that people can improve their health by adjusting the timing of their food. They add that avoiding or limiting feeding during nighttime hours can benefit night workers, those who have experienced insomnia or sleep-wake disorders, those with a variety of sleep/wake cycles, and those who travel frequently through time zones.

author: In addition to Scheer, Brigham’s large authors include Lei Gao, Jingyi Qian, Nina Vujovic, Peng Li and Kun Hu.

Disclosure: Scheer worked on the Sleep Research Association’s board of directors and received consulting fees at the University of Birmingham and Morehouse University.

Funding: This study was funded by grant number NIH R01HL118601 (ClinicalTrials.gov number: NCT02291952), 1UL1TR001102 and 1UL1TR002541-01. Funders did not play a role in the design of the research. Analyses or interprets collections, data. in writing a manuscript or in the decision to publish it.

Quote paper: Chellappa SL et al. “Daytime diet during simulated nightwork reduces changes in cardiovascular risk factors: a secondary analysis of randomized controlled TRIAsl” Natural Communication doi:10.1038/s41467-025-57846-y

For more information: