Night Owls Beware: Staying Up Late May Be Silently Damaging Your Heart

Are you a night owl who thrives on darkness? While you may find comfort in staying up late to watch your favourite television series or read an interesting book, a large study says it may be silently damaging your heart. The research from Harvard Medical School has found that those who are more active late at night, when most of the population is asleep, have poorer overall heart health. “It is not like that, night owls are doomed,” said Sina Kianersi, research fellow of Brigham and Women's Hospital and Harvard Medical School, who led the study. “The challenge is the mismatch between your internal clock and typically daily schedules that makes it harder to follow heart-healthy behaviours,” she added. However, according to the scientists, it is completely

fixable as well.

Your body’s internal clock and your heart

According to the American Heart Association, heart disease is the leading cause of death across the world, and not getting enough sleep is one of the major factors for issues like heart attacks and strokes. Your body runs on a circadian rhythm - a 24-hour internal clock that regulates sleep, release of hormones, blood pressure, and heart rate. This rhythm is closely tied to natural light and darkness, and when you stay up late under artificial light, especially screens, it confuses this system. Usually, your blood pressure and heart rate would come down at night, giving your heart a chance to rest and recover. However, keeping up till late at night and irregular sleep blunts the dip time, forcing your heart to work harder for longer periods. For months and years, this extra strain increases the risk of hypertension, heart attacks, and strokes. Kianersi said night owls might also have more health problems, as well as risk factors like higher rates of smoking and less physical activity, than those with more typical bedtimes.

How was the study conducted?

The team tracked more than 300,000 middle-aged and older adults in the UK Biobank, a huge health database that includes information about people’s sleep-wake preferences. About 8 per cent of those people classified themselves as night owls, more active physically and mentally in the late afternoon or evening, and up past most people’s bedtime. About a quarter were early birds, most productive in the daylight hours, and likewise early to bed. The rest were average, somewhere in the middle. Over a span of 14 years, the researchers observed that the night owls had a 16 per cent higher risk of a first heart attack or stroke compared to the average population. The night owls, especially women, also had overall worse cardiovascular health, the researchers reported in the Journal of the American Heart Association.

What are the main reasons behind it?

According to the scientists, three important unhealthy behaviours include:

• Smoking
• Insufficient and unregulated sleep
• Poor diet

According to the researchers, the metabolism of night owls fluctuates throughout the day as their bodies produce insulin to turn food into energy. That means it might be harder for them to handle a high-calorie breakfast eaten very early in the day, during what normally would still be their biological night. And if they go out late at night, it can be harder to find healthy food choices. Kianersi also said it is important to complete at least seven to eight hours of sleep daily and stick to a regular bedtime and wake time. Stress and mental health play a role. Late sleepers often experience higher levels of stress, anxiety, or irregular work schedules, which can further elevate heart risk through sustained activation of the body’s stress response.Also read: “I’m Fit; I Don’t Smoke”: Why a 35-Year-Old CrossFit Athlete Still Had a Heart Attack

How can night owls take care of their heart?

While it is not possible to instantly become an early bird, and genetics do play a role in sleep preference, experts say night owls can reduce risk with a few small and realistic changes, like:

• Go to bed and wake up at the same time daily, even on weekends.
• Reduce screen exposure at least an hour before bed
• Avoid heavy meals, alcohol, and caffeine at night
• Prioritise morning light exposure and regular physical activity to reset the body clock.