Stopping food three hours before bed and slightly lengthening an overnight fast improved blood pressure, heart rhythms, and blood-sugar control in adults at risk for cardiometabolic disease, a study from Northwestern Medicine, Chicago, Illinois, found.

Researchers found that middle age and older adults at elevated risk for cardiometabolic disease benefited from extending their overnight fasting window by roughly two hours. They also avoided food and dimmed lights for three hours before going to sleep.

These changes led to measurable improvements in heart and metabolic markers during sleep and throughout the following day.

"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," said corresponding author Phyllis Zee, MD, PhD, director of Northwestern’s Center for Circadian and Sleep Medicine and chief of sleep medicine.

The 7.5-week  trial included 39 overweight/obese adults (36 to 75 years old; 80%, women). Participants were assigned either to an extended overnight fasting group (13 to 16 hours of fasting) or to a control group that maintained a habitual fasting window (11 to 13 hours). Both groups dimmed lights three hours before bedtime.

Those who adjusted their timing experienced several meaningful changes. Nighttime blood pressure decreased by 3.5%, and heart rate dropped by 5%. These shifts reflected a healthier daily pattern, with heart rate and blood pressure rising during daytime activity and falling at night during rest. A stronger day/night rhythm is associated with better cardiovascular health.

Participants also demonstrated improved daytime blood sugar control. When given glucose, their pancreas responded more effectively, suggesting improved insulin release and steadier blood sugar levels.

Given the nearly 90% adherence in this trial, the researchers believe anchoring time-restricted eating to the sleep period may be a realistic and accessible non-pharmacological approach, especially for middle age and older adults who face higher cardiometabolic risk.

To read the abstract of the study, published in Arteriosclerosis, Thrombosis, and Vascular Biology, click here