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Over the last few years, research on cardiometabolic health has increased.
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Previous research shows that people can improve their cardiometabolic health by making healthy lifestyle choices, such as eating a healthy diet and getting enough quality sleep.
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A new study says that aligning overnight fasting with the body’s natural circadian rhythm may help improve cardiovascular and metabolic health markers.
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The researchers saw the most benefit from fasting at least 12 hours, as part of a time-restricted eating plan.
Over the last few years, there’s been an increase in research regarding cardiometabolic health, which combines a person’s cardiovascular system and metabolic system.
Cardiometabolic health takes into account certain risk factors derived from both systems, such as obesity, high blood pressure, increased glucose levels, and low HDL cholesterol, which can increase a person’s chances of developing several serious health conditions, including type 2 diabetes, heart attack, stroke, non-alcoholic fatty liver disease (NAFLD), and dementia.
Previous research shows that people can improve their cardiometabolic health by making healthy lifestyle choices, such as eating a nutritious and heart-healthy diet, moving more, managing stress, not smoking, maintaining a healthy weight, and getting enough quality sleep.
“Cardiometabolic health is strongly related to brain health, and what is emerging is that sleep health may mediate some of these effects,” Phyllis Zee, MD, PhD, director of the Center for Circadian and Sleep Medicine and the chief of sleep medicine in the department of neurology at the Feinberg School of Medicine at Northwestern University, told Medical News Today.
Zee is the lead author of a new study published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology, part of the American Heart Association, that found aligning overnight fasting, as part of a time-restricted eating plan, with the body’s natural circadian rhythm may help improve cardiovascular and metabolic health measurements both while at sleep and when awake during the day.
“As our life span increases, so should our healthspan, and critical to this is cardiometabolic and brain health. So, research to improve cardiometabolic health has implications for prevention of disease, as well as improvements in quality of life.”
— Phyllis Zee, MD, PhD
A specific window of time-restricted eating
For this randomized controlled study, researchers recruited 39 adults between the ages of 36 and 75 who were diagnosed as overweight or obese.
Half of the participants were asked to complete an extended overnight fasting cycle of 13–16 hours, or stick to a usual overnight fasting window of 11-13 hours, as the control group.
“There is evidence that time-restricted eating duration has beneficial effects on metabolic health,” Zee said. “However, most studies did not focus on the timing of the fasting period.”
“Because we know that sleep and circadian rhythms are important regulators of cardiometabolic health, we anchored the timing of the fasting to sleep time, and were able to evaluate the effect on cardiometabolic function during the night (sleep) and day (wake). Maintaining a healthy rhythm of day/night physiology is important for health,” she explained.
“Furthermore, (the study) was designed to be practical – stop eating three hours before sleep, stop exposure to bright light, and extend fasting period to at least 12 hours and eat what you normally eat,” she added.
How eating 3 hours before bed affects blood sugar and pressure
At the study’s conclusion, Zee and her team found that study participants who finished eating at least three hours before bed experienced improvements in their nighttime blood pressure levels, which decreased by 3.5%, and in their heart rate, which decreased by 5%.
“In addition to finishing eating three hours before bedtime, (participants) also extended the duration of the overnight fasting time,” Zee explained. “The decrease in blood pressure and heart rate indicates a healthy pattern during sleep, indicating ‘dipping,’ which is considered to be a healthy pattern.”
Additionally, these participants also experienced better blood sugar control during the day.
“For middle-aged and older adults who may be overweight, a healthy diet together with avoiding bright light and stopping eating two to three hours before bedtime, while maintaining an overnight fasting duration of about 12-14 hours, may benefit cardiovascular health during day and night,” Zee added.
Timing of eating may be as important as quality
MNT spoke with Cheng-Han Chen, MD, a board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, about this study, who commented that it is promising to see that such relatively straightforward interventions could provide benefits to cardiometabolic health.
“Cardiometabolic conditions such as high blood pressure, impaired glucose tolerance, and obesity are all known significant risk factors for heart disease. It is essential that we tackle these conditions through all possible means in order to reduce the burden of cardiovascular disease in our society.”
— Cheng-Han Chen, MD
“Future research will be necessary to confirm these findings in a larger and more diverse population,” Chen added.
MNT also spoke with Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist (RDN) and owner of Nutrition-In-Sight, who said that this study continues to add to the compilation of data that reinforces what we’ve long suspected, in that timing, in addition to quality and total intake, matters.
“This study adds meaningful data suggesting that aligning food intake with our biological clock — and extending the overnight fasting window — may improve both nighttime physiology and next-day cardiometabolic markers,” Richard added.
How can I fast overnight in a healthy way?
For readers who may want to try overnight fasting to potentially improve their cardiometabolic markers, like blood pressure and daytime blood sugar management, we asked Richard for her top tips.
“First, I emphasize this type of pattern is not about extreme fasting and does not work for every individual — there are a lot of factors, per person, to consider,” she advised. “It’s about creating a consistent overnight rest period for the metabolic system.”
Aside from getting sound advice from an RDN and your healthcare team about your individually tailored needs, Richard offered these general tips for exploring and implementing an overnight fasting pattern:
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Start gradually: If you typically snack at 10:30 pm, shifting to 9:30 pm consistently is progress forward until maybe you’re finished after dinner at 7:30 pm. Sustainable change is more beneficial than dramatic change.
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Ensure adequate overall daytime intake: Late-night eating is often the body trying to compensate for under-eating earlier in the day.
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Front-load nutrition earlier in the day: There’s something to be said about the age-old adage, “Eat breakfast like a king, lunch like a prince, and dinner like a pauper.” Research consistently shows improved glycemic control when calories are distributed earlier rather than heavily at night. Strive for a balanced breakfast, a substantial lunch, and a moderate, satisfying dinner.
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Protect sleep: Poor sleep drives late-night cravings by dysregulating the hunger and satiety hormones ghrelin and leptin. Improving sleep hygiene (quality and duration) supports metabolic pathways and regulation.
“Think of overnight fasting as metabolic housekeeping — your body needs uninterrupted time to reset,” Richard said. “Keep in mind, metabolic health is built on rhythm, quality, and consistency, not extremes. We also can not address what we don’t know. Tap into the expertise and resources of an RDN and healthcare team to find what would work best for your and your needs.”
View the original article on Medical News Today.
