Night Owls May Face Higher Risk of Heart Attack and Stroke, Large Study Suggests

People who regularly stay up late could face a greater risk of serious cardiovascular problems, according to new research examining how sleep timing influences long-term health.

The study found that individuals who identify as “evening types” — those whose energy peaks later in the day — were more likely to experience poor heart health compared with early risers. Researchers reported a 16% higher risk of heart attack or stroke among late sleepers.

The findings were published in the Journal of the American Heart Association and drew on data from more than 300,000 adults with an average age of 57. Roughly 8% of participants described themselves as strongly inclined toward late-night activity.

Lead researcher Sina Kianersi of Brigham and Women’s Hospital and Harvard Medical School indicated that people who favor late schedules often experience a mismatch between their internal body clock and typical daytime routines. This misalignment can coincide with habits known to influence heart health, including poorer diet quality, smoking, and insufficient sleep.

To evaluate cardiovascular wellbeing, researchers analyzed factors such as cholesterol, blood pressure, blood sugar, weight, exercise levels, diet, smoking status, and sleep quality. The results showed that night-oriented participants had a significantly higher prevalence — about 79% greater — of poor cardiovascular health indicators.

The association appeared particularly strong among women, though the reasons for this difference were not fully explained in the research.

Experts caution that the study has limitations. Chronotype — whether someone is naturally a morning or evening person — was determined using a single self-reported question, meaning sleep preferences could shift over time and may not have been fully captured.

Still, specialists say the results offer practical guidance rather than a cause for alarm. Kristen Knutson, a professor at Northwestern University who was not involved in the research, suggested that many of the risks are tied to behaviors that can be adjusted.

Health professionals emphasize that staying up late does not automatically lead to illness. Instead, maintaining consistent sleep schedules, avoiding smoking, staying physically active, and prioritizing balanced nutrition may help reduce cardiovascular risk regardless of one’s natural sleep preference.

Underlying the discussion is the role of circadian rhythms — the biological processes that regulate the body’s 24-hour cycle. When these rhythms are disrupted by irregular sleep, nighttime light exposure, shift work, or frequent travel, studies have linked the effects to conditions such as obesity, high blood pressure, type 2 diabetes, and heart disease.

Researchers say targeted health programs tailored to late sleepers could further support healthier routines. For now, the message is less about forcing night owls into early mornings — and more about ensuring that whatever the schedule, the habits surrounding it support long-term heart health.