A new study from Northwestern Medicine indicates that stopping eating three hours before bed and extending overnight fasting can improve blood pressure, heart rate, and blood sugar control without reducing calorie intake. Participants aligned their eating with natural sleep cycles, leading to measurable cardiometabolic benefits. The research highlights the importance of meal timing relative to sleep.
Researchers at Northwestern University Feinberg School of Medicine investigated how aligning time-restricted eating with the body's circadian rhythm affects cardiovascular and metabolic health. The study, published on February 12, 2026, in Arteriosclerosis, Thrombosis, and Vascular Biology, involved 39 overweight or obese adults aged 36 to 75. Participants were divided into two groups: one that extended their overnight fast to 13 to 16 hours by stopping eating at least three hours before bedtime and dimming lights during that period, and a control group maintaining a habitual 11 to 13-hour fast.
The intervention group, which was 80% women, achieved nearly 90% adherence over the 7.5-week trial. Results showed a 3.5% decrease in nighttime blood pressure and a 5% drop in heart rate, promoting a healthier day-night rhythm where these metrics rise during activity and fall at rest. Daytime blood sugar control also improved, with better pancreatic response to glucose, indicating enhanced insulin release.
"Timing our fasting window to work with the body's natural wake-sleep rhythms can improve the coordination between the heart, metabolism and sleep, all of which work together to protect cardiovascular health," said first author Dr. Daniela Grimaldi, research associate professor of neurology in the division of sleep medicine.
Corresponding author Dr. Phyllis Zee, director of the Center for Circadian and Sleep Medicine, added, "It's not only how much and what you eat, but also when you eat relative to sleep that is important for the physiological benefits of time-restricted eating."
The findings build on prior data showing only 6.8% of U.S. adults had optimal cardiometabolic health from 2017 to 2018, increasing risks for conditions like type 2 diabetes and cardiovascular disease. Funded by the National Institutes of Health, the team plans larger trials to refine the approach, viewing it as an accessible non-drug option for middle-aged and older adults at higher risk.
