Par euronews in Arabic
Published on •Updated
Analyzes show that staying up late is often associated with unhealthy daily habits, including poor-quality diet, insufficient sleep and high rates of smoking, which contribute to an increased risk of cardiovascular disease. According to the researchers, these results open up real possibilities for improving heart health by changing daily behaviors.
The study analyzed health data from more than 300,000 adults with an average age of 57 who took part in the UK Biobank study. Researchers sought to understand the relationship between chronotype – the natural preference for sleep and wakefulness – and indicators of heart health.
Participants were categorized based on their reported chronotype: about 8% of them went to bed around 2 a.m. and were more active late in the day, while 24% tended to go to bed and get up early.
The majority of them, 67%, were placed in an intermediate category that did not clearly fit either pattern.
Heart health was measured using the 8 Essential Life Criteria, which include a healthy diet, regular physical activity, absence of smoking and quality of sleep, as well as physiological indicators such as body weight, cholesterol, blood sugar and blood pressure, allowing for a comprehensive assessment of heart health.
Clearer differences among women
Comparisons between groups showed that people with a night work schedule were 79% more likely to have a poor overall rating of their heart health than the average group. They were also 16% more likely to have a heart attack or stroke during an average follow-up period of 14 years.
This association was stronger among womenthan in men, which suggests the possible existence of sex-specific effects. In contrast, the prevalence of poor heart health ratings was 5% lower among morning people compared to those who were not clearly labeled.
Researchers believe that much of this risk is due to lifestyle factors, particularly smoking and lack of sleep. Sina Kianiressi, lead researcher on the study, explains that people who work evening shifts often experience a mismatch between their internal body clock and the natural light cycle or society-imposed daily schedules, which can lead to behaviors that negatively impact heart health.
Despite these indications, experts stress that these results do not mean that heart disease is inevitable among night owls.
Kirsten Natson, who chaired the American Heart Association‘s 2025 Statement on Circadian Rhythm and Heart Health, points out that elevated risk is partly due to modifiable behaviors, providing opportunities to improve health through adequate sleep, reduced smoking and better diet. She also highlighted the importance of aligning health interventions and treatments with each individual’s biological clock.
Additional sources • adaptation: Jean-Philippe Liabot
