January 28, 2026
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People who stay up late consistently are more likely to have heart attacks or strokes than those who get up early in the morning, new research shows. But the finding is partly attributable to modifiable lifestyles, scientists say.
Being a night owl has its advantages – like having the energy to do more activities after school or work, or staying awake for late-night TV. But going to bed later on a regular basis may not be so good for the heart, a new study says.
The research found people who reported later bedtimes and more activity late in the day had worse cardiovascular outcomes than people who went to bed early and were more active early in the day – results that were especially pronounced among women.
The findings, published by the American Heart Association, partly may be due to lifestyle issues that night owls are more likely to engage in. These include smoking, poorer dieting habits and inadequate sleep. Also, staying up later may affect the body's natural rhythms – all factors that could lead to a higher incidence of heart disease, the researchers said.
"'Evening people' often experience circadian misalignment, meaning their internal body clock may not match the natural day-to-night light cycle or their typical daily schedules," said lead study author Sina Kianersi, a research fellow in the division of sleep and circadian disorders at Brigham and Women's Hospital and Harvard Medical School.
The study involved more than 300,000 adults with an average age of 57. About 8% said they were "definitely evening people" with late bedtimes, such as 2 a.m., and peak activity late in the day. About 24% said they were "definitely morning people" with early bedtimes, such as 9 p.m., and peak activity early in the day. And about 67% said they were "intermediate" because they either were unsure which category they fell into or they did not view themselves as morning or evening types.
To assess the participants' cardiovascular status, the researchers used the American Heart Association's checklist of optimal lifestyle factors for good heart health, such as managing blood pressure and quitting tobacco use.
Night owls had a 79% higher prevalence of poor cardiovascular health scores. The correlation between being a night owl and poor cardiovascular health was stronger in women than in men.
But the higher risk of cardiovascular disease for evening people is not solely due to sleep issues — and that's sort of rosy spot for night owls, said Kristen Knutson, a researcher who chaired the AHA's 2025 statement on the role the circadian system plays on cardiovascular and metabolic health. She was not involved in the new study.
"These findings show that the higher heart disease risks among evening types are partly due to modifiable behaviors such as smoking and sleep," Knutson said. "Therefore, evening types have options to improve their cardiovascular health. Evening types aren't inherently less healthy, but they face challenges that make it particularly important for them to maintain a healthy lifestyle."
The study also found that night owls had a 16% higher risk of having a heart attack or stroke over a median of about 14 years follow-up, compared to people within the intermediate category. Early birds had a 5% lower prevalence of low heart health scores compared to those without a strong morning or evening preference.
Interestingly, a 2024 study found that people who were more alert at night seemed to have a cognitive advantage over morning people by scoring better on certain tests.
