A major study of more than 322,000 adults has found that people who naturally stay awake late at night may have poorer heart health and a higher risk of heart attack or stroke. The encouraging finding: much of the risk appears linked to habits that can be changed.
Whether you are a “night owl” who loves the quiet of the midnight hours or an “early bird” who catches the worm, your internal clock might be telling you more about your heart than you think.
A major new study published in the Journal of the American Heart Association (JAHA) tracked over 322,000 adults to see how our natural sleep-wake preferences, known as our chronotype, impact our heart health.
Major study followed more than 322,000 adults
Researchers analysed data from 322,777 adults aged 39 to 74 years in the UK Biobank.
Participants described themselves as morning people, evening people or somewhere in between.
Around 8% were definite evening people or “night owls”. About 24% were definite morning people, while roughly 67% fell into the intermediate group.
Researchers then examined their heart health using the American Heart Association’s Life’s Essential 8 measures. The results raised an important question about late-night living.
Night owls had 79% higher prevalence of poor heart health
Compared with people who had neither a strong morning nor evening preference, definite night owls had a 79% higher prevalence of poor overall cardiovascular health scores. Why take SO MUCH UN-NECCESSARY RISK – could be a way of looking at this data.
Over a median follow-up of about 14 years, evening people also had a 16% higher risk of heart attack or stroke. The link between evening preference and poor heart health was also stronger in women than in men.
These numbers sound worrying. But the study found something equally important.
Being a night owl may not be the real problem
The increased heart risk appeared to be linked largely to modifiable health habits and risk factors. Night owls were more likely to have poorer diet quality, smoke or use nicotine and get inadequate or irregular sleep.
This means the message is not that staying up late directly causes a heart attack. The problem may arise when a person’s natural body clock clashes with work, family and social schedules.
Researchers call this circadian misalignment.
In simple language, your body may want to sleep and wake later, while your job demands that you wake at 6 am. A night owl may go to bed at 2 am but still need to wake at 6.30 am. The result can be chronic sleep loss and irregular sleep timing.
Why may night owls develop poorer heart health? The study points towards several possible reasons. A person awake late at night may find it harder to maintain regular sleep. Late-night eating may affect diet quality. Early work schedules can cut total sleep time. Smoking and nicotine use were particularly important factors in the study.
The American Heart Association said that poor heart health habits and factors, especially nicotine use and inadequate sleep, explained much of the increased cardiovascular risk seen in evening people.
Your body clock may influence your health habits. Those habits, in turn, may influence your heart.
The eight heart health factors night owls should watch
The researchers assessed cardiovascular health using the American Heart Association’s Life’s Essential 8. These are:
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Eat a healthier diet
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Be physically active
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Avoid tobacco and nicotine
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Get healthy and timely sleep
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Maintain a healthy weight
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Control cholesterol
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Manage blood sugar
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Control blood pressure


