Top Things to Know: Role of Circadian Health in Cardiometabolic Health & Disease Risk
Published: October 28, 2025
- The circadian system includes a central clock in the hypothalamus and peripheral clocks throughout the body, which regulate ~24-hour rhythms in several physiological systems, including cardiovascular and metabolic function.
- “Circadian health” refers to the optimal function, rhythmicity and alignment of all internal circadian rhythms to each other and to the external light-dark cycle. Circadian health is important for maintaining physiological and behavioral health, including cardiovascular function.
- Light is the primary external time cue synchronizing our central circadian clock, and other time cues can include meals, sleep and physical activity. Therefore, inopportune or irregular timing of light, sleep, physical activity and meals can disrupt circadian rhythms.
- Rotating and night shift work is a common cause of circadian disruption and has been associated with increased risk of obesity, diabetes, hypertension, and cardiovascular disease.
- Irregular sleep timing has also been associated with cardiometabolic outcomes, including increased prevalence of obesity, type 2 diabetes, and cardiovascular disease (CVD). This highlights that sleep timing (and regularity) is another important dimension of sleep health beyond sleep quantity.
- The timing of meals can affect metabolic health beyond the caloric content of the meals. Later timing of meals tends to be associated with worse cardiometabolic outcomes, including diabetes, high blood pressure, and CVD.
- Light exposure timing is a therapeutic tool that can modify circadian timing, but its effect depends on its timing relative to a person’s internal clock (as opposed to the external clock). Therefore, the timing of light exposure must be carefully considered and personalized.
- Timing of physical activity may also help to improve circadian rhythmicity and may enhance circadian health. Optimal timing, however, needs to be identified and will be relative to the person’s internal clock.
- Circadian health can play an important role in equitable health, since poor circadian health (or circadian disruption) can exacerbate cardiometabolic health disparities, disproportionately affecting individuals in low-resource settings.
- Optimizing circadian rhythms through behavioral modifications is a promising approach for cardiometabolic disease prevention that warrants more investigation.
Citation
Knutson KL, Dixon DD, Grandner MA, Jackson CL, Kline CE, Maher L, Makarem N, Martino TA, St-Onge M-P, Johnson DA; on behalf of the American Heart Association Council on Lifestyle and Cardiometabolic Health; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; and Council on Lifelong Congenital Heart Disease and Heart Health in the Young. Role of circadian health in cardiometabolic health and disease risk: a scientific state¬ment from the American Heart Association. Circulation. Published online October 28, 2025. doi: 10.1161/CIR.0000000000001388