July 9, 2026

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When it comes to healthy habits, most people think about what they eat. However, new research suggests that what time you eat — especially in relation to overnight sleep — also may play an important role in heart health.

A study led by Daniela Grimaldi, M.D., Ph.D., Research Associate Professor, Department of Neurology, Center for Circadian and Sleep Medicine, and Phyllis C. Zee, M.D., Ph.D., Director, Center for Circadian and Sleep Medicine, Chief of Sleep Medicine, Department of Neurology, and Benjamin and Virginia T. Boshes Professor of Neurology at Northwestern University Feinberg School of Medicine, explores a simple idea: aligning an overnight fast with the body’s natural sleep cycle. The team’s findings — published in Arteriosclerosis, Thrombosis, and Vascular Biology — suggest that aligning fasting with sleep may help create conditions that support heart health overnight and during the day.

Time-restricted eating (TRE) is a dietary strategy that limits food intake to a set number of hours each day. Previous studies suggest that TRE can support weight management, metabolic health and blood pressure control, making it a popular topic among researchers and wellness advocates. However, Zee noted that most TRE studies have not taken the body’s internal clock, or circadian sleep-wake rhythm, into account.

“We know sleep is an important regulator of cardiometabolic and cardiovascular function, but none of these studies really looked at what was happening during the sleep period,” Zee said. “We don’t really know what’s going on through the entire circadian rhythm of cardiovascular physiology.”

With support from the NCATS Clinical and Translational Science Awards (CTSA) Program, Zee and her team tested an approach they call “sleep-aligned eating.” They set up a clinical trial in which participants stopped eating about 3 hours before bedtime, resulting in an overnight fasting period of roughly 13 to 16 hours.

The experimental design was tailored to each participant’s typical sleep schedule. “It’s a practical way for people to think about it,” Zee said. “You just decide when you want to stop eating, and from that point, you count the hours until your next meal.” A distinctive feature of the study was that participants dimmed their lights for several hours before bedtime, as exposure to bright light in the evening is known to affect cardiometabolic health.

The study included adults who were generally overweight and at risk for diabetes but had not been diagnosed with the disease. Over a 6- to 7- week period, participants tracked their eating and sleep habits while researchers monitored their glucose levels, cardiac function and blood pressure at home using wearable devices. The researchers also measured other markers of metabolic health — including cortisol and insulin sensitivity — during overnight measurements in the laboratory.

The study revealed several significant findings. Participants who followed the sleep-aligned fasting schedule showed lower heart rates, reduced diastolic blood pressure and lower cortisol levels during nighttime sleep. Together, these changes suggest a calmer, more restorative cardiovascular state during sleep. The team also observed greater differences between daytime and nighttime heart rates, suggesting that TRE may help strengthen the body’s natural circadian cardiovascular rhythm. Notably, the researchers originally set out to measure changes in insulin sensitivity, but that primary outcome did not improve significantly — a result that could be explored in future studies.

Overall, these findings highlight a growing understanding that sleep is not just a period of rest but an active time when the body regulates key processes, including cardiovascular function and metabolism. Although the results come from an early study and are not yet sufficient to support broad clinical recommendations, they suggest that small, everyday changes — such as adjusting when you eat — may help support long-term heart and metabolic health. Further research could help determine whether this approach has a role in reducing cardiovascular and metabolic disease risk.

Michael Kurilla, M.D., Ph.D., director of NCATS’ Division of Clinical Innovation, which administers the CTSA Program, commented on the significance of the findings for public health. He stated, “Identifying and validating simple, cost-free interventions that improve health may prove more efficacious with greater uptake than more costly drug solutions.”

The findings also align with broader NIH efforts to better understand how everyday behaviors influence long-term health. By exploring how the body’s internal clock influences health and applying those insights into everyday habits, the study reflects NCATS’ mission to turn scientific discoveries into practical strategies that may improve health. If confirmed in larger studies, sleep-aligned eating could represent a simple, accessible approach to supporting cardiovascular and metabolic health and reducing disease risk.

Looking ahead, Zee and her colleagues hope to expand the research to include larger sample sizes and more diverse populations, including people with type 2 diabetes or those at higher risk for cardiovascular disease. They also plan to study how factors such as sex, age and individual sleep patterns may influence the results. For now, Zee says, the takeaway is simple. “Try to stop eating 3 hours before bedtime,” she said. “Dim your lights and be mindful of the duration of your eating window.”