New data shows that staying up late is associated with poorer cardiovascular health in adulthood and old age, especially among women.
Middle-aged and older adults who are more active in the evening have poorer cardiovascular health than those who are active earlier in the day, according to a large study based on data from the UK Biobank and recently published in the Journal of the American Heart Association (JAHA), an open-access scientific journal of the American Heart Association (AHA).
The analysis included more than 300,000 participants, with an average age of about 57 years, and looked at the connection between chronotype, namely the natural preference for sleeping and waking hours, and the condition of the heart and blood vessels.
The participants were classified according to the declared pattern: approximately 8% identified themselves as active people in the evening, who fall asleep very late, sometimes around 2 am, and reach the maximum level of activity later in the day; about 24% were active people in the morning, who go to bed early, for example around 9 p.m., wake up early and are more active in the first part of the day; the remaining approximately 67% were considered without a clear preference.
Cardiovascular health was assessed by the AHA’s Life’s Essential 8 score, which takes into account eight components known for their role in maintaining heart health: diet, physical activity, smoking, sleep quality, body weight, cholesterol, blood sugar and blood pressure.
Compared to people in the intermediate category, those active in the evening were 79% more likely to have a poor overall cardiovascular score.
In addition, over a median follow-up of about 14 years, this group had a 16% higher risk of myocardial infarction or stroke.
The link between an activity performed predominantly in the evening and a poorer state of cardiovascular health was more pronounced in women than in men.
Much of the increased cardiovascular risk observed in people active in the evening was explained by lifestyle factors, particularly nicotine consumption and insufficient sleep.
In contrast, people who were active in the morning had a 5% lower risk of poor cardiovascular health compared to people who did not identify themselves as either active in the morning or active in the evening.
The study authors note that these results point to an important role of the timing of daily activity in long-term heart health. They point out that habits more common among people active in the evening, such as poorer diet quality, smoking and insufficient or irregular sleep, contribute to these differences.
Although the study shows a clear association, it does not suggest that people who go to bed late are inevitably less healthy. On the contrary, the results indicate that changing some behaviors, such as quitting smoking and improving sleep, could reduce the risk of heart attack and stroke in this group.
The researchers also note limitations of the analysis: the majority of UK Biobank participants are white and generally healthier than the general population, and chronotype was assessed only once, based on self-report. The study was partially funded by the American Heart Association.
