Circadian disruption and its impact on the cardiovascular system

The circadian clock is recognized as a central regulator of cardiac function; misalignment of biological rhythms can impact cellular processes over the course of the day and promote cardiovascular disease (CVD).The timing of environmental cues (light and behavior) affect cardiometabolic health by modulating metabolism, blood pressure (BP), lipids, body mass index, inflammation, and diabetes.Maintaining a normal diurnal pattern for BP is essential for cardiovascular health. Lifestyle modification and medication taken at night are proposed to have greater benefits for nighttime BP dipping and overall BP levels as well as for cardiometabolic function and maintenance of cardiac rhythms.Day-to-day variability in sleep and timing of eating is increasingly linked with elevated CVD risk and severity of disease; however, data linking sleep variability and biomarkers of atherosclerosis are lacking.Entrainment of the circadian clock through exercise has been reported to improve health by reducing risk of CVD via modulation of circadian control of hormonal levels, sleep/wake cycles, BP, and heart rate.Adjusting mealtimes, modulating light exposure and sleep schedules, timing of exercise and chronotherapy have the potential to adjust internal circadian rhythms, may improve outcomes for patients with heart disease, and mitigate increased CVD risk in shift workers, who have a 30% higher risk for CVD compared with the general population. Circadian rhythms are highly conserved biorhythms of ~24 h that govern many fundamental biological processes, including cardiovascular (CV) homeostasis. Disrupting the timing of cellular oscillators promotes cellular stress, and induction of pathogenic pathways underpins the pathogenesis of many CV diseases (CVDs). Thus, shift work, late eating, sleep disturbances, and other disruptors can result in an elevated risk of heart disease and increased incidence of adverse CV events. Here, we discuss the importance of circadian rhythms for CV homeostasis, recent developments in understanding the impact of disrupted circadian rhythms on CV health and disease progression, and how understanding the interactions between circadian and CV physiology is crucial for improving interventions to mitigate CVD, especially in populations impacted by disrupted circadian rhythms. Circadian rhythms are highly conserved biorhythms of ~24 h that govern many fundamental biological processes, including cardiovascular (CV) homeostasis. Disrupting the timing of cellu