New research using wearable technology finds that inconsistent bedtimes can significantly raise the risk of heart disease for people who sleep less than 8 hours, even when other risk factors are considered.
Most people pay attention to how many hours they sleep, but new research shows that when you go to bed and how regular that bedtime is, could be just as important for your heart. A large study that followed thousands of adults for a decade found that people who get less than eight hours of sleep and have varying bedtimes face twice the risk of major heart problems compared to those with steady sleep routines.
How wearable tech revealed a hidden pattern
Researchers used accelerometers, similar to advanced fitness trackers, to monitor 3,231 adults from the Northern Finland Birth Cohort 1966. These devices recorded bedtime, wake-up time, and the midpoint of sleep over seven days. The technology closely matched sleep diaries within about 20 minutes and smart rings within 5 minutes.
Participants wore the trackers between 2012 and 2014. Their health was then tracked through 2023, focusing on major heart issues and deaths. This approach gave scientists real-world, objective sleep data, which is more accurate than relying on people’s memories.
To measure how much sleep timing changed from night to night, the researchers calculated bedtime variation for each person. Participants were divided into groups with low, medium, or high irregularity for further analysis.
The risk grows when sleep gets off track
Over the ten-year follow-up, 128 people experienced serious heart events, such as heart attacks, strokes, or deaths linked to cardiovascular disease. The study found that irregular sleep patterns only raised the risk in people who slept less than the group’s average of 7 hours and 56 minutes per night, which is close to the usual recommendation of 8 hours.
For those sleeping less than eight hours, going to bed at different times and having an inconsistent sleep midpoint both independently doubled the risk of major heart issues. In other words, if you get less than eight hours and your bedtime changes a lot, your chances of heart problems are much higher than for those who stick to a regular routine.
These findings held up even after accounting for other known risks like high blood pressure, body mass index, cholesterol, and physical activity. Interestingly, wake-up time did not show a strong link to heart risk. This points to the importance of keeping your bedtime steady, rather than focusing only on when you wake up.
What happens when sleep falls out of sync
Scientists think that irregular sleep disrupts your circadian rhythm, the body’s natural clock that controls key functions like blood pressure and inflammation. When your bedtime shifts from night to night, these internal systems can become unbalanced, raising your chances of developing heart disease.
Other studies using different ways to measure sleep regularity, such as the Sleep Regularity Index, have found similar results. The message is clear: the more unpredictable your sleep schedule, the higher your risk for heart issues. However, getting enough sleep might help protect you even if your bedtime isn’t always the same.
The research also noted that unemployed participants faced a higher risk of heart problems, regardless of their sleep habits. This highlights the role of mental health, since stress and depression can affect both employment and sleep, creating a cycle that’s tough on the heart.
A closer look at the study’s strengths and gaps
This study stands out because it used wearable devices to objectively track sleep, instead of relying on people’s recollections. The long follow-up period and detailed health tracking make the findings more reliable. By excluding participants who developed heart problems early, the researchers reduced the chance that heart disease was causing sleep issues, not the other way around.
However, the participants were mostly white and middle-aged, so it’s unclear if the findings apply to other groups. There were also a limited number of heart events, and only a week of sleep data was collected, though past research suggests this is enough to spot patterns.
Easy steps to steady your sleep and help your heart
If you often get less than eight hours of sleep, making your bedtime more consistent could help protect your heart. Simple changes, like keeping a regular pre-sleep routine or avoiding late-night meals, can make a difference.
The research also shows that whether you’re naturally a morning or night person isn’t as important as keeping your sleep schedule steady. The main takeaway is that regular sleep habits matter, especially for those who don’t get enough rest each night.
As the researchers noted,
These findings highlight the importance of consistent sleep behavior, particularly regular bedtimes, as a potential target for health promotion.
Future studies may look at whether improving sleep regularity can actually lower heart risks over time, which could lead to new advice for better heart health.
The future of sleep tech
Since the study was performed, sleep tech has advanced consistently, moving from basic sleep and heart rate tracking to optimization. Devices like Sleepal impressed scientists at CES with their smart design and multiple functions. This smart AI lamp does not require wearing or physical contact.
It accurately tracks users’ breathing, snoring, and sleep position, while also measuring room temperature, light, and humidity, and provides detailed sleep reports and optimization suggestions. With its help, users not only have a complete overview of their sleep, but they also have a solid plan on how to optimize it and, more importantly, tools to do so.
From self-adjusting bedroom lights to breathing and meditation exercises and white noise and soundscapes, Sleepal users have everything they need to improve their sleep and protect their heart rate at their fingertips.
Learn more about Sleepal and its innovative functions here!