Sleepless Nights & Heart Troubles: Is Insomnia or Night Shift Work to Blame?
"New research disentangles the complex relationship between sleep disorders, shift work, and cardiovascular disease in nursing professionals, offering critical insights for healthcare workers and employers."
Cardiovascular diseases (CVDs) and poor sleep are known to be linked, but the impact of specific work schedules, like night shifts, has been less clear. Many studies look at CVD and work schedules separately, potentially missing crucial connections. New research investigates the combined effects of insomnia and night work on CVD risk among female nursing professionals, aiming to disentangle these complex relationships.
The study, published in the Brazilian Journal of Medical and Biological Research, involved 1307 female nurses from three public hospitals. Researchers analyzed the association between insomnia and self-reported physician diagnoses of CVD in both day and night workers. A key aspect was considering all sleep episodes, including both nocturnal and diurnal (daytime) sleep, particularly important for night workers who often sleep during the day.
By examining these factors together, the study aimed to determine whether CVD risk is more closely tied to night work itself or to the sleep disturbances that often accompany it. This distinction is critical for developing targeted interventions to protect the health of nursing professionals and potentially other shift workers.
Insomnia’s Cardiovascular Impact
Insomnia is described by the American Heart Association as one of the most common sleep disorders, affecting the ability to fall asleep, stay asleep, or obtain good sleep. Its symptoms can include daytime sleepiness, low energy, and difficulties with concentration, focus, and memory. A 2026 Frontiers in Psychiatry article notes that insomnia remains underdiagnosed and undertreated in coronary heart disease care, where clinical attention has disproportionately focused on sleep-disordered breathing. The CDC’s National Center for Health Statistics provides official sleep-health statistics through its FastStats application.
Multimodal Sleep Care
The sources describe approaches that address sleep through more than one dimension, including sleep hygiene, behavioral modification, self-management, and cognitive behavioral therapy for insomnia (CBT-I). Research in adults with chronic heart failure has evaluated changes in sleep-health phenotypes after CBT-I or attention-based interventions rather than focusing on a single sleep characteristic. A systematic review reports a randomized study of 34 patients comparing general sleep education combined with web-based CBT-I against general sleep education alone followed by a wait-list treatment opportunity. However, the precise relationship between insomnia subtypes and subsequent heart-failure risk remains poorly understood.
Insomnia, Not Just Night Work, Increases CVD Risk
The study revealed a significant association between insomnia and CVD, regardless of whether participants worked during the day or night. Among day workers, those with insomnia complaints had a 2.79 times greater chance of reporting a CVD diagnosis compared to those without sleep issues. Night workers reporting insomnia during both nocturnal and diurnal sleep periods showed a 3.07 times greater chance of CVD.
- Day Workers: Insomnia complaints increased the odds of CVD by 2.79 times.
- Night Workers: Insomnia during both night and day sleep increased the odds of CVD by 3.07 times.
- Key takeaway: The likelihood of reporting CVD was similar for both day and night workers experiencing insomnia.
Shift Work and Sleep Quality
A cross-sectional study of U.S. adults reported a positive association between evening or night work schedules and coronary heart disease or angina. That study also emphasized the role of sleep quality in the occurrence of coronary heart disease and angina among evening or night workers. A systematic review of healthcare shift workers found that night workers had significantly poorer sleep quality than day or evening workers, including shorter sleep duration, greater daytime dysfunction, and poorer overall sleep quality. Research on shift work disorder likewise compares night workers with and without the disorder and day and night workers with insomnia.
Separating Insomnia From Night Work
Evidence does not uniformly show that night work itself explains cardiovascular risk. In nursing professionals, the probability of self-reporting a physician diagnosis of cardiovascular disease was similar among day and night workers with insomnia, suggesting an association with insomnia rather than night work per se. Observational and Mendelian-randomization studies have found strong associations between insomnia and cardiovascular disease, but Mendelian-randomization findings on causality have been inconsistent. Meta-analytic evidence has nevertheless reported significant longitudinal associations between different insomnia symptoms and incident heart failure.
A Bidirectional Relationship
A 2026 synthesis reported that insomnia was associated with a 45% increase in cardiovascular disease risk across 15 cohort studies involving 2.1 million participants, while cardiovascular disease could in turn worsen sleep. Another review described insomnia as a consistent, dose-dependent cardiovascular risk factor but noted that trials have not shown that treating insomnia lowers cardiovascular risk. Circadian rhythms influence sleep-wake cycles as well as blood pressure, vascular tone, endothelial function, insulin sensitivity, and inflammation. These findings frame insomnia and cardiovascular disease as interconnected while leaving the benefits of treatment for cardiovascular prevention unresolved.
Protecting Your Heart: Prioritizing Sleep for All
This study provides valuable insights for nursing professionals and other shift workers concerned about their cardiovascular health. The key takeaway is that addressing insomnia and improving sleep quality should be a priority, regardless of when you work. Simple steps, such as optimizing sleep environment, regular sleeping routine or seeking help from a sleep specialist may help in managing work-related sleep disturbances.
Digital and Home-Based Care
The SLEEP 2026 Annual Meeting in Baltimore, held June 14–17, featured new research on insomnia’s cardiovascular risk, shift work, digital CBT-I, and home sleep diagnostics. The meeting’s clinical summary indicates that these areas are emerging fronts in research and care. Digital CBT-I may broaden access to behavioral treatment, while home sleep diagnostics could support assessment outside traditional clinical settings. The available source identifies these developments but does not establish whether they reduce cardiovascular events.
Persistent Symptoms Matter
Large prospective cohort studies and meta-analyses have consistently associated insomnia symptoms and clinically diagnosed insomnia with higher risks of hypertension, myocardial infarction, stroke, heart failure, and cardiovascular mortality. The reported associations are stronger among people with short sleep duration or persistent insomnia. Recent research also links chronic insomnia symptoms with an elevated risk of incident heart failure and suggests a dose-response pattern based on the number and severity of symptoms. These findings highlight why persistent sleep problems can have consequences beyond nighttime discomfort.
For employers, these findings highlight the need to implement strategies that support the sleep health of their employees, especially those working non-traditional hours. This could include offering sleep health education, providing resources for managing insomnia, and creating work environments that promote rest and recovery.
Ultimately, recognizing sleep disturbance as a public health concern and prioritizing sleep for everyone, not only benefits individual health but also enhances workforce well-being and productivity.