Research Highlights:

• Sleep regularity may be a critical factor for heart health, researchers said.
• Having highly inconsistent bedtimes or varying sleep duration from night to night was linked to a higher risk of heart attack, stroke, heart failure and other cardiovascular events, according to data analyzed from more than 1 million nights of sleep.
• Note: The study featured in this news release is a research abstract. Abstracts presented at American Heart Association’s scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

DALLAS - November 2, 2026 (NEWMEDIAWIRE) - Maintaining a consistent sleep schedule may be an important factor to consider for protecting the heart, according to new, independent, preliminary research to be presented at the American Heart Association’s Scientific Sessions 2026. The meeting, Nov. 6–9, in Chicago, is a premier global exchange of the latest scientific advancements, research and evidence-based clinical practice updates in heart and stroke science.

 “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,” said 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.

Researchers analyzed sleep data from more than 10,000 adults who wore an activity tracking device as part of the National Institutes of Health’s “All of Us” Research Program.

What did the analysis track?

• Sleep quantity - how many total hours a person slept each night;
• Sleep quality - how much of the night was spent in light, deep and REM sleep, and how long a person was awake after first falling asleep;
• Sleep regularity - how sleep duration, bedtime and wake-up time changed from night to night;
• Sleep timing - the usual times a person fell asleep and woke up, and the midpoint between them, which is related to chronotype, or a person’s natural tendency to be a ‘night owl’ or an ‘early bird’; and
• Sleep cycles - the number of sleep cycles completed each night (the interval from the end of the one REM period to the end of the next, including the light and deep stages in between) and the duration of each cycle.

What were the main findings?

• Changes in sleep timing from night to night over about a six-month period were linked to a 20% to 23% higher risk of serious heart events, including heart attack, stroke and heart failure.
• Each 29-minute increase in how much a person's sleep length varied from night to night was associated with a 24% higher risk of the combined cardiovascular outcome, including a 29% higher risk of having a disease of the heart muscle, which leaves the heart unable to pump enough blood through the body, and a 20% higher risk of heart failure.
• Having a greater number of complete sleep cycles each night was associated with a 28% lower risk of atrial arrhythmia, a common type of irregular heartbeat.
• An unusually long sleep cycle was linked to a 55% higher risk of heart attack or stroke.

Irregular sleep was linked to a much wider range of heart conditions than expected, Viet noted.

“Sleep irregularity is often due to weekends - we get to sleep a little bit later on a Friday night; or people have shift work. This may not be good for your heart health,” Viet said. “Sometimes the quality of sleep is something we cannot control. But the regularity, consistent bedtimes throughout the week and waking up at the same time every morning, is something some people can control.”

The study findings should be interpreted cautiously, said American Heart Association volunteer expert Marie-Pierre St-Onge, Ph.D., C.C.S.H., FAHA, who chaired the Association’s 2025 scientific statement: Multidimensional Sleep Health: Definitions and Implications for Cardiometabolic Health and was not involved in this study.

”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,” said St-Onge, a professor of nutritional medicine and director of the Center of Excellence for Sleep & Circadian Research at Columbia University Irving Medical Center in New York City. “However, contrary to the years of research showing how insufficient sleep affects cardiovascular risk factors, we are still lacking the data to support a causal, independent impact of sleep regularity on cardiovascular disease risk. This study should prompt scientists to further evaluate links between sleep regularity and cardiovascular disease, so that we can make the same recommendations for regularity that we can for duration.

“Sleep duration and regularity often interact in their relation to heart disease risk. This abstract notes an additional tool to consider when working on improving sleep. Adopting stable sleep schedules can be helpful to achieve better sleep duration as well.”

Study details, background, design and limitations:

• Researchers pieced together data for more than 1 million nights of sleep from 10,362 adults participating in the National Institutes of Health’s “All of Us” Research Program.
• Among study participants, average age 53, about 69% were women, and 81.6% self-reported as white adults, 4.6% as Black adults, 3.1% as Asian adults and 10.7% as another race or did not report race. None had heart or metabolic disease at the start of the study.
• Sleep was characterized over a roughly a 6-month baseline window, and participants were then followed for a median of 3.7 years for cardiovascular events.
• The analysis was adjusted for multiple factors, including age, sex, race, education, income, smoking, alcohol use, cancer and mental health conditions.
• Study limitations include that, as an observational study, it could not establish cause and effect. In addition, sleep stages were measured with wearable devices while participants slept at home rather than brain-monitoring equipment in a sleep lab, the standard practice for sleep studies.

Co-authors, disclosures and funding sources are listed in the abstract.

Statements and conclusions of studies that are presented at the American Heart Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association’s scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

The Association receives more than 85% of its revenue from sources other than corporations. These sources include contributions from individuals, foundations and estates, as well as investment earnings and revenue from the sale of our educational materials. Corporations (including pharmaceutical, device manufacturers and other companies) also make donations to the Association. The Association has strict policies to prevent any donations from influencing its science content and policy positions. Overall financial information is available here.

Additional Resources:

• Multimedia, including video interview clips with American Heart Association volunteer expert, American Heart Association volunteer expert, Marie-Pierre St-Onge, Ph.D., C.C.S.H., FAHA, is available on the right column of the release link.
• Spanish news release
• Link to abstract; and the American Heart Association’s Scientific Sessions 2026 Online Program Planner
• American Heart Association news release: Body clocks matter for heart health (Oct. 2025)
• American Heart Association news release: Sleep matters: duration, timing, quality and more may affect cardiovascular disease risk (April 2025)
• American Heart Association news release: Erratic sleep patterns linked to elevated blood pressure in teens with extra belly weight (March 2023)
• American Heart Association news release: Irregular sleeping habits may increase risk of atherosclerosis in older adults (Feb. 2023)
• American Heart Association health information: American Heart Association adds sleep to cardiovascular health checklist (June 2022)
• About Scientific Sessions 2026
• For more news at the American Heart Association’s Scientific Sessions 2026, follow us on X @HeartNews, #ScientificSessions26

 About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. Dedicated to ensuring equitable health in all communities, the organization has been a leading source of health information for more than one hundred years. Supported by more than 35 million volunteers globally, we fund groundbreaking research, advocate for the public’s health, and provide critical resources to save and improve lives affected by cardiovascular disease and stroke. By driving breakthroughs and implementing proven solutions in science, policy, and care, we work tirelessly to advance health and transform lives every day. Connect with us on heart.org, Facebook, X or by calling 1-800-AHA-USA1.

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