Late sleepers face higher heart disease risk, UK study finds

People who prefer staying up late may face a higher risk of heart disease, largely driven by poorer overall cardiovascular health, according to a large new study based on UK Biobank data.

The study, titled “Chronotype, Life’s Essential 8, and Risk of Cardiovascular Disease: A Prospective Cohort Study in UK Biobank”, has been published in the Journal of the American Heart Association.

Researchers analysed data from 3,22,777 adults aged 39 to 74 years who had no known cardiovascular disease (CVD) at the start of the study. Participants self-reported their sleep–wake preference — whether they were morning types, evening types, or intermediate — and were followed for a median of 13.8 years to track new cases of heart attack and stroke.

The study found that individuals who preferred “definite evening” were significantly more likely to have poor cardiovascular health. Compared to people with an intermediate chronotype, evening types showed a 79% higher prevalence of a poor Life’s Essential 8 (LE8) score, a composite measure that assesses eight key heart health factors, including diet, physical activity, sleep, blood pressure, cholesterol, blood sugar, smoking, and body weight.

During the follow-up period, researchers recorded 17,584 cardiovascular events, including 11,091 heart attacks and 7,214 strokes. After adjusting for factors such as age, sex, socioeconomic status, shift work and family history of heart disease, people with a definite evening chronotype had a 16% higher risk of developing cardiovascular disease compared to those with an intermediate chronotype.

Crucially, the analysis showed that around 75% of the increased CVD risk among evening types was explained by poorer LE8 scores, suggesting that lifestyle and cardiometabolic risk factors play a dominant role. In contrast, people with a definite morning chronotype did not show a significantly increased risk.

The researchers noted that circadian misalignment in evening chronotypes may disrupt health behaviours and metabolic functions, contributing to worse cardiovascular profiles over time. They emphasised that the elevated risk could be reduced through targeted interventions.

The authors concluded that people with an evening chronotype may benefit the most from focused strategies to improve cardiovascular risk factors, such as better sleep routines, healthier diets, regular physical activity and improved metabolic control.

The study was led by Sina Kianersi and colleagues, including researchers from multiple international institutions.