Circadian misalignment, which occurs when our behavioral cycles are out of sync with the body’s internal clock, is a known consequence of shift work
While working night shifts has long been linked to increased health risks, especially for the heart, a new study suggests that simply changing when food is consumed could offer significant protection. Researchers from Mass General Brigham in the US and the University of Southampton in the UK found that eating only during the daytime may prevent cardiovascular problems caused by circadian rhythm disruption.
The study, published in Nature Communications, shines new light on how food timing – not just sleep patterns – can influence heart health. While sleep disruptions have been a major focus in the past, the research team believes that the timing of meals may play an even greater role in managing cardiovascular risks associated with night shift work.
Circadian misalignment, which occurs when our behavioral cycles are out of sync with the body’s internal clock, is a known consequence of shift work. This misalignment can lead to a range of serious health issues, particularly related to the heart. Previous studies have shown increased risks of obesity, diabetes, high blood pressure, and other cardiovascular conditions among night workers.
In the latest study, researchers worked with 20 healthy young adults in a strictly controlled laboratory environment for two weeks. During this time, participants were completely cut off from external time cues—they had no access to natural light, clocks, or electronic devices. This allowed scientists to isolate the effects of internal circadian rhythms from external factors.
Participants first went through a 32-hour period of continuous wakefulness in dim lighting, maintaining a consistent body posture while consuming identical hourly snacks. Following this, they entered a phase simulating night work, and were randomly assigned to two groups: one ate only during daytime hours, while the other ate during nighttime hours, mimicking typical shift worker behavior.
Importantly, both groups followed an identical nap schedule, ensuring that any observed differences were not the result of varying sleep durations or quality. The key variable under investigation was when participants ate their meals.
The results were striking. In those who ate at night, researchers observed increases in several cardiovascular risk markers, including blood pressure, plasminogen activator inhibitor-1 (a protein that raises the risk of blood clots), and autonomic nervous system imbalances. In contrast, participants who ate only during daytime hours showed no such increase in risk.
Lead author Dr. Sarah Chellappa, Associate Professor at the University of Southampton, emphasized the rigor of the study: “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.”
Professor Frank Scheer, co-author and director of the Medical Chronobiology Program at Brigham and Women’s Hospital, added that these findings offer a new avenue for reducing health risks among shift workers. “Avoiding or limiting eating during nighttime hours may benefit night workers, those with insomnia, individuals with irregular sleep patterns, and people who frequently travel across time zones.”
Although more research is needed to assess long-term outcomes, the team described the findings as “promising.” The message is clear: while the demands of night work may be unavoidable for many, adjusting meal times could be a simple yet powerful strategy to safeguard heart health. As millions around the world work through the night to keep essential services running, this research provides a beacon of hope—offering practical, non-invasive ways to protect well-being, even when the clock is working against us.
