Irregular Sleep Timing Linked to Higher Heart Risk
In a study of 10,000 Americans, shifting bedtimes from night to night were associated with a higher risk of heart attack, stroke and heart failure.
Updated on Nov. 2, 2026 in Sleep Disorders
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A study that tracked the sleep of 10,000 Americans for six months found that greater night-to-night variation in sleep timing was linked to a higher risk of heart attack, stroke and heart failure. The findings draw on sleep-tracking data from more than one million nights and were presented alongside related research at major heart meetings.
Why it matters
Most public advice focuses on how many hours adults sleep, but this research suggests that how consistent sleep is from night to night may also matter for heart health. The work is observational, so it can show association but not prove that irregular sleep causes heart disease.
The findings come from an observational study that followed 10,000 Americans for six months of sleep tracking and four years of heart-health follow-up, analyzing more than one million nights of sleep. The associations are reported as relative risks, and the study does not establish that irregular sleep directly causes heart disease.
The players
American Heart Association
The American Heart Association is a leading national organization focused on cardiovascular disease prevention, research and public health.
The details
Participants wore sleep-tracking devices for six months, and researchers measured sleep cycles, defined as the interval from the end of one REM period to the end of the next. Greater variation in sleep length and timing from night to night was linked to higher rates of heart problems, while more complete sleep cycles each night were linked to lower atrial arrhythmia risk. Irregular sleep is often caused by later sleep onset on Friday nights or by shift work.
Timeline
Sleep tracking for the US study ran for six months.
Participants were followed for four years to assess heart problems.
The findings were presented at the American Heart Association Scientific Sessions 2026 in Chicago.
Health Landscape
Sleep duration recommendations of 7 to 9 hours per night have long been the main benchmark for adult sleep health. This research adds sleep regularity as a separate measure that may be relevant to cardiovascular risk.
If you have noticed large swings in when you fall asleep or wake up, it may be worth raising sleep regularity with your doctor during a routine checkup. Keeping a steadier sleep schedule, including on weekends, is a low-risk habit the findings support.
The takeaway
Sleep consistency may matter for heart health alongside total sleep duration. Talk with your physician about any sleep patterns or heart symptoms that concern you.
Further reading
For broader context on how sleep patterns affect the body, explore our coverage of Sleep Disorders.
Live Poll
Do you think keeping a consistent sleep schedule matters for your heart health?
