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Circadian-aligned eating can benefit heart health.

Eating in-sync with your bedtime can support cardiovascular recovery.

Sleep is a pillar of heart health. Aim to stop eating at least three hours before bedtime.

These days, we are often bombarded with nutrition advice. Eat more protein, cut carbs, count calories, to fast or not fast? But one part of the conversation that is largely ignored is when we eat in relation to our body’s internal clock, otherwise known as our circadian rhythm.

As a sleep scientist, I was fascinated by new research from the Northwestern University Feinberg School of Medicine that conducted a randomized clinical trial to evaluate how the timing of fasting, specifically its alignment with each person’s natural sleep-wake rhythm, can influence heart health.

Rather than simply extending the fasting window or cutting more calories, the intervention group was simply asked to finish eating at least three hours before their usual bedtime. That meant no snacking while watching TV after dinner and no “just one more bite” at 10 p.m. (my personal downfall). This relatively simple intervention ensured that the overnight fast overlapped with the body’s natural sleep-wake rhythm.

The results were impressive. Those who followed the circadian-aligned fasting plan saw significant improvements in nocturnal blood pressure dipping (i.e., greater declines in nighttime blood pressure, indicating greater recovery), as well as lower nighttime heart rate, higher heart rate variability, lower nighttime cortisol, and lower glucose levels, tested via an Oral Glucose Tolerance Test.

As a clinical psychologist who knows how difficult behavior change can be, what also struck me about these findings was the high rate of compliance with the circadian-aligned fasting intervention. Nearly 90 percent of participants randomized to the intervention were adherent to the fasting schedule. That’s a remarkable level of adherence for a behavioral intervention, suggesting that these findings could translate beyond the confines of a tightly controlled trial into real-world settings. In other words, stopping eating at least three hours before bedtime may be a sustainable and effective strategy that people can comply with in everyday life.

Heart disease remains the leading cause of death for both men and women. While there has long been a focus on diet and exercise, rightly, as key prevention pillars when it comes to cardiovascular health, sleep is increasingly being recognized as an additional pillar. In fact, the American Heart Association now includes healthy sleep among its “Life’s Essential 8” for cardiovascular health.

These findings are particularly exciting because they connect the dots between sleep, circadian rhythms, and nutrition. It is not only that sleep independently affects cardiovascular risk. Sleep and circadian rhythms also shape how our bodies respond to other behaviors, including diet. Aligning meals so that digestion settles long before bedtime may give the cardiometabolic system a better opportunity to recover overnight.

In the age of advancement in personalized and precision medicine, the next frontier may be circadian-aligned timing of interventions. That means thinking not just about what is prescribed, whether it is a lifestyle intervention or a medication, but when it is timed in relation to an individual’s biological clock. Future heart-health strategies might not only ask what we eat and how much we move, but when our bodies are most ready for those activities. Sometimes the path to better health isn’t about doing more or trying harder, it's about better timing.

Why Is Sleep Important?

Take our Sleep Habits Test

Find a sleep therapist near me

https://www.ahajournals.org/doi/10.1161/ATVBAHA.125.323355

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