Night owls may be at greater risk of heart attack and stroke, new research suggests. The study, which followed more than 300,000 adults for nearly 14 years, found that people who habitually go to bed late and wake late were more likely to have poorer cardiovascular health and a higher incidence of major cardiovascular events than those with more conventional sleep schedules.

The finding is important, clear and actionable. Most of the excess risk is linked to modifiable behaviours rather than to the biological preference for later sleep times.

Researchers examined data from a large population cohort in the United Kingdom. Participants were aged between 39 and 74 at enrolment, had no prior heart attack or stroke, and answered questions about their sleep preference. They self‑classified as definitely morning, definitely evening or somewhere in between. The majority described themselves as intermediate; roughly one in four were morning types and about 8% defined themselves as evening types.

Cardiovascular health was measured using a standardised framework that combines behavioural and clinical measures into a single score. This metric incorporates diet, physical activity, nicotine exposure, sleep, body weight, blood pressure, blood sugar and cholesterol. The framework creates a composite view of heart health that goes beyond single risk factors and provides a practical guide to prevention.

After almost 14 years of follow‑up, the picture was striking. People who identified as evening chronotypes had a substantially higher prevalence of poor cardiovascular health compared with the intermediate group.

That group also experienced a higher rate of heart attack and stroke. The difference translated into a 79% greater prevalence of poor overall cardiovascular health in evening types, and an approximately 16% higher risk of major cardiovascular events compared with the intermediate group.

The disparity was not uniform across all risk components. Evening types scored worse on six of the eight elements of the cardiovascular score. Tobacco use was the largest single contributor to the excess risk among evening chronotypes. Poor sleep measures also explained a meaningful portion. In short, the bulk of the association between later sleep timing and worse heart outcomes appears to be explained by lifestyle patterns that cluster with the evening preference, rather than by chronotype alone.

That conclusion offers a clear public health message. Chronotype itself is largely determined by intrinsic circadian biology and is not readily changed. But behaviours that commonly accompany a late chronotype are modifiable.

These include smoking, poor diet, physical inactivity, unfavourable body weight, suboptimal blood pressure and cholesterol control, and inadequate sleep quality or duration. Addressing these factors can substantially reduce cardiovascular risk, regardless of when an individual prefers to sleep.

If a person identifies as a night owl, clinicians and public‑health practitioners might focus on targeted interventions to tackle smoking, improve sleep habits, encourage physical activity, support dietary change and promote better management of blood pressure, lipids and blood sugar. For evening chronotypes, such efforts may yield large returns because they address the main drivers of the observed risk.

The study also found sex differences: the association between evening preference and poorer cardiovascular health appeared more pronounced in women. That detail merits further investigation. It could reflect differential behaviour patterns, biological differences in circadian regulation, or disparities in how risk factors interact with sex. The current data cannot resolve these possibilities, but they point to the need for sex‑sensitive prevention strategies.

Shift workers represent a related group for whom the findings are particularly relevant. Overnight or rotating shifts force many people to sleep at biologically suboptimal times, creating misalignment between the body’s internal clock and external schedules. That misalignment can impair sleep quality, disturb metabolic regulation and alter appetite and activity patterns.

Shift workers, like voluntary night owls, tend to accumulate poorer sleep and to adopt less favourable dietary and activity habits. Practical steps for those who cannot avoid nocturnal work include prioritising sleep recovery on off days, securing healthy food choices during shifts, and attempting to keep a consistent sleep schedule where feasible.

Wearable devices and other consumer technologies can help monitor sleep, activity and heart rhythm, but they cannot substitute for clinical assessment when medical concerns arise.

The study used self‑reported chronotype, which has strengths and limits. Self‑classification is easy to obtain in clinical and epidemiological settings and reflects how people live their days. Yet it is less precise than objective measures of circadian phase derived from biomarkers or actigraphy.

The cohort was predominantly white and middle aged to older at baseline. That limits the generalisability of the findings to younger populations and to more ethnically diverse groups. Nonetheless, the size of the cohort, the lengthy follow‑up and the comprehensive cardiovascular scoring lend weight to the results.

The study’s message dovetails with an established prevention strategy that is simple and evidence based.

The cardiovascular framework used by the authors highlights eight modifiable domains: stopping smoking, increasing physical activity, optimising sleep, achieving a healthy weight, controlling cholesterol, managing blood sugar, maintaining healthy blood pressure, and improving diet. Achieve those, and cardiovascular risk falls — substantially.

A recent report estimated that a sizeable proportion of premature cardiovascular deaths could be avoided if populations reached optimal scores across these domains.

Why might evening preference cluster with unfavourable habits? The reasons are multiple and behavioural. Later sleep schedules often mean more evening socialising, greater exposure to late food and drink, higher opportunity for nicotine use, reduced opportunities for morning exercise, and potential misalignment with work or family routines that favour earlier schedules.

In addition, late sleepers sometimes accumulate sleep debt when societal schedules force early starts. That debt impairs daytime function and can push people towards energy‑dense foods and sedentariness. Over time, these patterns produce the metabolic and vascular changes that raise cardiovascular risk.

The findings do not mean that everyone who goes to bed late will have poor heart health. Many people maintain healthy lifestyles while keeping late hours.

The key point is that being a night owl is associated with a higher prevalence of behaviours known to harm the cardiovascular system. Changing those behaviours matters.

For clinicians, the study supports routine attention to sleep timing as one piece of a comprehensive risk assessment. Asking patients when they usually sleep and wake can unveil patterns that influence smoking, diet, activity and sleep quality.

For public‑health planners, the results underline that prevention strategies should consider chronotype and work schedules when designing interventions. For employers and policymakers, the implications are clear: work schedules that respect circadian biology where feasible, and measures to support healthy choices during non‑traditional hours, may yield population health benefits.

What individuals can do right now is straightforward. If you consider yourself an evening person, focus on the basics. Stop smoking. Move more. Improve your diet. Check and manage blood pressure, cholesterol and blood sugar in collaboration with a clinician. Prioritise good sleep hygiene and try to recover lost sleep promptly. Keep healthy food options available during late hours. Use wearable technology if it helps you track and correct patterns. For those who must work nights, seek strategies to stabilise sleep and align meals and activity with the realities of shift work.

The research community has more to explore. Whether a mismatch between an individual’s intrinsic chronotype and their work schedule further magnifies cardiovascular risk remains an open question. Longitudinal studies that include objective measures of circadian timing, diverse populations, and interventions aimed at the identified modifiable behaviours will clarify the causal pathways and inform tailored prevention programmes.

Night owls show a higher prevalence of poor cardiovascular health and a small but meaningful increase in heart attack and stroke risk. Most of the difference is explained by changeable behaviours. That makes the finding both concerning and encouraging. Concerning because late chronotypes are a non‑negligible portion of the population; encouraging because targeted lifestyle changes can substantially reduce risk.

Pay attention to sleep timing, yes, but focus first on the fundamentals of heart health.