Staying up late isn’t a free pass for heart trouble, but it does raise the risk. A massive new UK study, tracking over 17,000 cardiovascular events, reveals that lifestyle choices—specifically, getting enough sleep, quitting smoking, and managing your metabolism—can significantly blunt the danger posed by being a night owl.
Can Your Sleep Schedule Predict Heart Disease Risk?
Is being a night owl really that bad for your heart? The answer is complicated, but a new study suggests that lifestyle factors can play a crucial role in mitigating the risks associated with a late chronotype.
- Cardiovascular disease remains the leading cause of death globally.
- Individuals with a later sleep-wake cycle (“evening chronotype”) face a modestly increased risk of heart attack or stroke.
- Healthy habits—adequate sleep, avoiding smoking, and maintaining a healthy weight—can substantially reduce this risk.
- The study tracked over 17,500 cardiovascular events over a 13.8-year period.
Cardiovascular disease (CVD) continues to be the world’s number one killer. While diet, exercise, and avoiding tobacco are well-established strategies for reducing risk, recent guidance from the American Heart Association (AHA) highlights the often-overlooked importance of sufficient sleep.
How Circadian Rhythms Impact Heart Health
Our internal “body clock,” or circadian rhythm, influences not only when we sleep and wake but also a host of physiological processes. People vary in their natural sleep-wake timing—their chronotype—and research suggests that certain rhythms are linked to a higher risk of cardiometabolic problems. Those with an evening chronotype, for example, are more prone to circadian disruption.
This misalignment can throw off brain functions related to reward and behavior, potentially leading to unhealthy habits like a poor diet, excessive alcohol consumption, and smoking. Chronic disruption also impacts the nervous system, blood pressure, glucose and lipid levels, and hormone regulation.
UK Biobank Study Links Chronotype, Lifestyle, and CVD
Researchers analyzed data from 39,368 participants in the United Kingdom Biobank, aged between 39 and 74, who had no prior history of heart attack or stroke. Participants self-reported their chronotype, and cardiovascular health was assessed using the Life’s Essential 8 (LE8) score—a measure encompassing diet, exercise, nicotine exposure, sleep, weight, blood glucose, cholesterol, and blood pressure.
The study followed participants for a median of 13.8 years, during which 17,584 new CVD events occurred—7,214 strokes and 11,091 heart attacks. The average LE8 score was 67, with slightly higher scores for women (70) compared to men (65). Seven percent of participants had unfavorable LE8 scores below 50.
Approximately 67 percent of participants identified as having an intermediate chronotype, while 8 percent were “definitely evening” types. Those with a “definitely evening” chronotype tended to be younger, more likely to be deprived, less educated, and employed in shift work.
Participants with an intermediate chronotype had an average LE8 score of 68, compared to 65 for those with a “definitely evening” chronotype. Poor LE8 scores were roughly 79 percent more common among evening types, while those with a “definitely morning” chronotype had approximately 5 percent lower prevalence of low LE8 scores.
Six of the eight LE8 components were worse in those with an evening chronotype, with blood pressure and blood lipids being the exceptions. Nicotine use and insufficient sleep showed the strongest associations with poor LE8 scores.
Among morning chronotypes, poor sleep was 30 percent more likely, while a poor diet was less common. Women with an evening chronotype were nearly twice as likely (96 percent higher) to have low LE8 scores, compared to a 67 percent higher prevalence among men.
Evening Types Face 16% Higher CVD Risk—But It’s Not Inevitable
CVD risk increased by 16 percent among participants with an evening chronotype. This association was more pronounced, though not statistically significant, among older individuals, men, non-shift workers, and those with low LE8 scores. Researchers found no evidence that genetic predisposition to cardiovascular disease altered the effect.
Importantly, approximately 75 percent of the association between chronotype and CVD risk was explained by the LE8 score. Nicotine use accounted for the largest portion of this risk (34 percent), while sleep, blood glucose, body weight, and diet each contributed 11–14 percent.
Study Limitations and Future Research
This study is the first to explore the role of the LE8 score in mediating the link between chronotype and CVD. Its strengths include a prospective design, a long follow-up period, and the consideration of multiple health behaviors. The large sample size also enhanced statistical power.
However, the study’s reliance on a single self-reported chronotype question could introduce some misclassification, although responses correlated well with validated scores. The single assessment of chronotype and LE8 scores also limits certainty about the order of events—whether chronotype influences lifestyle or vice versa. Finally, the study population was predominantly White and relatively healthy, limiting the generalizability of the findings.
Q: Can I reduce my heart disease risk if I’m a night owl? A: Yes. This study shows that adopting healthier lifestyle habits—prioritizing sleep, quitting smoking, and managing your weight and blood sugar—can significantly offset the increased cardiovascular risk associated with a late chronotype.
