Irregular Sleep Routine May Be One of the Most Significant Risk Factors for Cardiovascular Diseases

A new study explores how regular and irregular sleep patterns affect cardiovascular health in middle aged to older adults with diverse ethnic background.

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Last Updated: Fri, April 21, 2023

Cardiovascular diseases are a group of conditions affecting blood vessels and heart, and they are the number one cause of death around the world, killing almost 18 million people each year, according to the World Health Organization.

When we talk about cardiovascular health prevention, exercise and diet get most of the spotlight. And although we do know that proper rest is also essential for our cardiovascular system, most recommendations focus solely on how long we sleep. A new study published in The Journal of the American College of Cardiology proposes that sleep patterns are a more significant risk factor for cardiovascular health than sleep duration. There are more factors determining sleep quality, and focusing only on sleep duration may not be the best solution when it comes to heart diseases.

Our internal clocks are responsible for keeping metabolism, heart rate, blood pressure, and sleep patterns running smoothly. So what exactly happens when the irregular sleep disturbs our internal clocks? Researchers from Brigham and Woman’s Hospital measured that exact effect.

The investigators examined data from the Multi-Ethnic Study of Atherosclerosis (MESA). The study included 1992 participants with diverse ethnic backgrounds and no history of cardiovascular diseases at the beginning. All the subjects were aged 45-84 years, and they were required to wear a wrist activity tracker for seven days. The device recorded their sleep activities and patterns.

After the initial measurements, participants were followed for five years on average. During that period, 111 subjects experienced a cardiovascular event, including strokes, heart attacks, and other adverse incidents.

Researchers then divided participants into four groups depending on their sleep patterns. When it comes to sleep duration, the most irregular group had more than two-hour difference on a night to night basis, while the most regular one had less than an hour. The investigators also considered consistency, and they compared subjects with the most consistent schedules against those whose bedtimes varied each night significantly.

The results showed that cardiovascular events were most common in people with the most irregular sleep patterns. In fact, they estimate that only 8 in 1000 people with regular sleep patterns would have a cardiovascular event over one year, while that number rises to 20 in people with an irregular sleep schedule.

These results show that sleep consistency is another important indicator of sleep quality, besides sleep duration. The authors expressed an interest in researching this topic even further. They want to know whether an intervention such as a more regular sleep schedule could decrease a person’s risk of a cardiovascular event. Until then, findings from this study confirm how important it is to maintain good sleeping hygiene.


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Dusan is a biologist, a science enthusiast and a huge nature lover. He loves to keep up to date with all the new research and write accurate science-based articles. When he’s not writing or reading, you can find him in the kitchen, trying out new delicious recipes; out in the wild, enjoying the nature or sleeping in his bed.