Sleeping late? Your bedtime might predict a heart attack; here’s what science says |
Sleep is essential for keeping the human body and heart in balance. It regulates blood pressure, metabolism, and overall cardiovascular function. Yet, in modern life, many people go to bed later because of long work hours or time spent on digital devices. Scientists are now learning that when we sleep may be just as important as how much we sleep. While poor or short sleep has long been known to raise the risk of heart problems, recent research has begun to explore whether bedtime itself plays a role. A new study published in Frontiers found that people who regularly go to bed after midnight on weekdays have a higher risk of heart attack. This discovery suggests that the timing of sleep could directly affect heart health.
How our body clock keeps the heart in rhythm
The human body follows a 24-hour internal clock known as the circadian rhythm. This clock helps control when we feel awake or sleepy and regulates vital functions such as blood pressure, hormone levels, and heart rate. The heart and blood vessels work in line with this natural rhythm, staying more active during the day and resting at night. When people stay up well past midnight, they interfere with this built-in schedule. Over time, this disruption can place extra strain on the cardiovascular system.In the Frontiers study, researchers found that people who regularly went to bed late on weekdays were more likely to experience a heart attack. Interestingly, this pattern did not appear on weekends, suggesting that weekday routines, combined with early wake-up times, may increase the heart’s workload. These results show that bedtime can influence heart health independently of sleep duration, highlighting the importance of aligning sleep with the body’s natural rhythm.
What the research revealed about bedtime and heart risk
The study examined information from 4,576 adults who took part in the Sleep Heart Health Study, which tracks sleep patterns and cardiovascular outcomes. Participants reported their usual bedtime and wake-up time for both weekdays and weekends. Their bedtimes were grouped into four ranges: before 10:00 pm, between 10:01 pm and 11:00 pm, between 11:01 pm and midnight, and after midnight. Researchers followed them for more than ten years to see who developed myocardial infarction, the medical term for heart attack.The results showed a clear pattern. Those who went to bed after midnight during weekdays were much more likely to have a heart attack than those who slept between 10:01 pm and 11:00 pm. Even after accounting for other risk factors such as smoking, body weight, high blood pressure, diabetes, alcohol use, and total sleep duration, the link remained strong. People with late weekday bedtimes had about a 63 per cent higher risk of heart attack. Interestingly, going to bed very early, before 10:00 pm, also carried a slightly higher risk, forming a U-shaped pattern where both extremes of bedtime appeared less favourable.
Why late nights can harm the heart
There are several reasons why staying up late might increase heart risk. First, delaying sleep disrupts the production of melatonin, a hormone that helps control blood pressure and supports repair of blood vessels during the night. Low melatonin levels can lead to higher blood pressure and more inflammation in the arteries. Late nights are also often linked to shorter and poorer-quality sleep, reducing the amount of deep rest the body needs to recover.People who stay up late may also adopt habits that harm the heart, such as eating late, being less physically active, and spending long hours exposed to bright screens. These behaviours can increase blood sugar and cholesterol levels, encourage weight gain, and heighten stress hormone activity. Over time, such changes can damage blood vessels and make heart attacks more likely. Laboratory studies have shown that irregular sleep timing raises cortisol, impairs glucose control, and increases blood clotting which are all factors that contribute to cardiovascular disease.
How regular sleep habits can protect the heart
The findings suggest that a consistent bedtime may help protect against heart problems. Going to bed around the same time each night supports the body’s internal clock and allows the cardiovascular system to rest and repair properly. Health researchers are beginning to recognise that sleep timing should be considered alongside diet, exercise, and smoking in assessing heart-disease risk.Late-night lifestyles have become common in modern society, with technology, shift work, and flexible schedules often pushing people to stay awake longer. This pattern can create “social jet lag”, where a person’s biological clock is constantly out of sync with daily routines. Over time, this misalignment may increase blood pressure, disturb metabolism, and raise the risk of obesity and diabetes, all key contributors to heart disease.Public-health experts suggest that improving sleep habits could be a simple but effective way to support heart health. Going to bed at a steady, reasonable hour and getting enough rest may help maintain healthy blood pressure, balance stress hormones, and lower inflammation. Although more research is needed to prove that changing bedtime directly reduces heart-attack risk, the current evidence makes one thing clear: the time we go to sleep could be just as important for heart health as how long we stay asleep.Disclaimer: This article is for informational purposes only and should not be considered medical advice. Please consult a healthcare professional before making any changes to your diet, medication, or lifestyle.Also Read | Do you have a habit of cracking your neck? That quick relief could be dangerous and cause a stroke
