Being a night owl may not be great for your heart but you can do something about it

Night Owls Face Higher Heart Health Risks, Study Finds

Being a night owl may come with unexpected health consequences, according to a large-scale study that reveals people who are most active late at night face poorer overall heart health compared to the general population.

Researchers from Brigham and Women’s Hospital and Harvard Medical School tracked more than 300,000 middle-aged and older adults over 14 years, finding that self-identified night owls had a 16% higher risk of experiencing their first heart attack or stroke compared to people with average sleep-wake patterns.

“It is not like night owls are doomed,” explained research fellow Sina Kianersi, who led the study. “The challenge is the mismatch between your internal clock and typical daily schedules that makes it harder to follow heart-healthy behaviors.”

This mismatch appears to be at the core of the problem. The body’s circadian rhythm—our master biological clock—regulates not only when we feel sleepy or alert but also controls vital functions including heart rate, blood pressure, stress hormone production, and metabolism. When someone’s natural rhythm conflicts with societal schedules, health consequences can follow.

Of the study participants, approximately 8% classified themselves as night owls—people who feel most physically and mentally active in late afternoon or evening and typically stay up past most people’s bedtime. About 25% identified as early birds, while the remainder fell somewhere in between.

The health disparity was particularly pronounced among women night owls, who showed worse overall cardiovascular health based on the American Heart Association’s eight key factors for heart health: physical activity, tobacco avoidance, adequate sleep, healthy diet, and control of blood pressure, cholesterol, blood sugar, and weight.

Kristen Knutson of Northwestern University, who wasn’t involved in the new study but led recent heart association guidance on circadian rhythms, explained the fundamental challenge: “It comes down to the problem of a night owl trying to live in a morning person’s world. They’re getting up early for work because that’s when their job starts, but it may not align with their internal rhythm.”

This misalignment affects more than just sleep patterns. Metabolism fluctuates throughout the day as the body produces insulin to convert food into energy. For night owls, eating a high-calorie breakfast early in the morning—during what their body still considers biological night—may be metabolically challenging. Additionally, finding healthy food options during late-night hours can be difficult.

The researchers identified unhealthy behaviors—particularly smoking, insufficient sleep, and poor diet—as the main contributing factors to night owls’ increased cardiovascular risk.

For those who identify as night owls, the researchers offer practical advice. While changing one’s chronotype entirely may be difficult, focusing on manageable health improvements can make a difference. Kianersi, who describes himself as “sort of a night owl,” recommends quitting smoking as one of the most impactful steps anyone can take for better heart health.

Even for those unable to get the recommended minimum seven hours of sleep, maintaining consistency in bedtime and wake time may help mitigate some risks. “Focus on the basics, not perfection,” Kianersi advises—guidance that applies universally.

The findings, published Wednesday in the Journal of the American Heart Association, highlight how lifestyle patterns intersect with our biological makeup to influence long-term health outcomes. As work schedules become increasingly flexible in many industries, the research underscores the potential health benefits of allowing people to align their work hours with their natural biological rhythms.

Heart disease remains the leading cause of death in the United States. While being a night owl represents just one of many factors influencing cardiovascular health, understanding these connections provides valuable insights for both individuals and healthcare providers working to reduce heart disease risk.