Preliminary research presented at the American Heart Association's Scientific Sessions 2026 indicates that sleep regularity—consistent bedtimes, wake times, and sleep duration from night to night—may be a critical factor for heart health. The study, which analyzed more than 1 million nights of sleep from over 10,000 adults, found that highly inconsistent sleep patterns were linked to a higher risk of heart attack, stroke, heart failure, and other cardiovascular events.
The analysis, part of the National Institutes of Health's "All of Us" Research Program, tracked sleep quantity, quality, regularity, timing, and cycles using wearable devices. Researchers found that changes in sleep timing from night to night over about a six-month period were associated with a 20% to 23% higher risk of serious heart events. Each 29-minute increase in how much a person's sleep length varied from night to night was linked to a 24% higher risk of the combined cardiovascular outcome, including a 29% higher risk of cardiomyopathy and a 20% higher risk of heart failure. Additionally, having a greater number of complete sleep cycles each night was associated with a 28% lower risk of atrial arrhythmia, while an unusually long sleep cycle was linked to a 55% higher risk of heart attack or stroke.
Lead researcher Nguyen Minh Tuan Viet, M.D., Ph.D., a neuroscientist and postdoctoral research fellow at Boston Children's Hospital and Harvard Medical School, emphasized the practical implications. "While we often focus on getting a full eight hours of sleep every night, having a regular sleep schedule - consistent bedtimes, wake times, and sleep duration from night to night is a practical, actionable step anyone can take that may help protect their heart and blood vessels," Viet said. He noted that sleep irregularity often stems from weekends or shift work, and while sleep quality may be beyond control, regularity is something some people can manage.
The findings add to a growing body of evidence linking sleep to cardiovascular health. The American Heart Association added sleep to its cardiovascular health checklist in 2022, and previous releases have highlighted how body clocks matter for heart health and how sleep duration, timing, quality and more may affect cardiovascular disease risk. Earlier studies also linked erratic sleep patterns to elevated blood pressure in teens with extra belly weight and found that irregular sleeping habits may increase risk of atherosclerosis in older adults.
However, experts caution that the study is observational and cannot establish cause and effect. Marie-Pierre St-Onge, Ph.D., C.C.S.H., FAHA, a professor at Columbia University Irving Medical Center who chaired the Association's 2025 scientific statement on Multidimensional Sleep Health: Definitions and Implications for Cardiometabolic Health, said, "This study highlights another potential important sleep characteristic to consider for heart health, which adds to the body of research we currently have on sleep duration." She added that data are still lacking to support a causal, independent impact of sleep regularity on cardiovascular disease risk, but the study should prompt further research.
The research will be presented at the American Heart Association's Scientific Sessions 2026 in Chicago, a premier global exchange of the latest scientific advancements in heart and stroke science. The abstract is available in the abstract and the 2026 Online Program Planner. A Spanish news release is also available.
