Irregular sleep patterns could put your heart health at risk.

A peer-reviewed study out this week in the Journal of the American Heart Association finds that sleeping an inconsistent number of hours each night and variations in bedtime could raise the risk of developing atherosclerosis for those age 45 and older, compared to those whose sleep patterns are consistent.

It’s one of the first studies to find a link between sleep habits and atherosclerosis, the buildup of fatty deposits on the walls of arteries. Those plaques lent atherosclerosis its nickname: hardening of the arteries. In a release on the study, the association said that “the plaque can cause arteries to narrow, reducing blood flow and the amount of oxygen and other nutrients reaching the body. Or the plaque may burst and create a blood clot that blocks the artery, which could lead to a heart attack or stroke.”

“Maintaining regular sleep schedules and decreasing variability in sleep is an easily adjustable lifestyle behavior that can not only help improve sleep, but also help reduce cardiovascular risk for aging adults,” said study lead author Kelsie Full, Ph.D., an assistant professor of medicine in the division of epidemiology at Vanderbilt University Medical Center, in the release.

Previous research has linked poor sleep quality to heart disease, high blood pressure, obesity, Type 2 diabetes and other heart-related challenges.

Among the study’s findings:

  • Those with sleep durations that varied more than two hours within a week were 1.4 times as likely to have more calcified plaque in their arteries — “the main underlying cause of cardiovascular disease events,” including stroke and heart attack.
  • When sleep duration varied more than two hours in a week, participants were 1.2 times more likely to have carotid plaque and almost twice as likely to have signs of systemic atherosclerosis and stiffness in the blood vessels.
  • Consistent bedtime matters. Those with sleep timing that varies more than 90 minutes within a week were 1.4 times more likely to have calcium build-up in their coronary arteries, compared to those who nod off at roughly the same time (within a half hour) every night during the week.
  • Sleep timing didn’t appear to significantly impact other cardiovascular disease markers.
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Nuts and bolts

For the study, the researchers tracked sleep patterns of a racially diverse group of 2,000 individuals, with an average age of 69 (the range was 45-84) who did not have cardiovascular disease. The study participants were recruited in six U.S. communities: St. Paul, Minnesota; Baltimore city and county in Maryland; Chicago; Forsyth County, North Carolina.; Los Angeles; and northern Manhattan and the Bronx in New York.

Between 2010 and 2013, the participants wore a wrist device that could tell when they slept and were awake as well as disruptions. They also completed a sleep diary for seven consecutive days and took part in a one-night at-home sleep study to look for sleep disorders like apnea, sleep stages, waking patterns and heart rate, among other things.

The researchers checked for calcified fatty plaque buildup in coronary arteries and in the carotid artery in the neck, thickness of certain neck arteries and whether the peripheral arteries were narrowed.

They also looked at health records and questionnaires to cull age, sex, race and ethnicity, education, yearly income, whether the participant was a smoker or consumed alcohol, physical activity, body mass index, blood pressure, sleep habits and work schedules, such as day shift or night shift.

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The study had some limitations, including the fact that sleep and atherosclerosis were measured together, which means they couldn’t prove that sleep irregularity causes the development of arterial plaque.

Why sleep matters

Sleep is so vital to health that it was recently added to the American Heart Association’s Life’s Essential 8 — a combination of health behaviors and health factors. The former, it notes, can be changed to improve overall health.

The eight, which are each presented online with a helpful fact sheet with information and tips, are:

Of sleep, the association notes most adults need seven to nine hours each night, while babies and kids need more. Not getting enough increases the risk of heart disease, cognitive decline and dementia, depression, high blood pressure, high blood sugar and high cholesterol, as well as obesity.

During sleep, the body repairs cells, tissues and blood vessels, the American Heart Association says. Sleep is good for the immune system and for mood and energy. Healthy sleep improves brain function and reduces the risk of chronic disease, per the association.

According to University of Chicago News, “Good sleep hygiene includes strategies such as developing a bedtime routine that helps you wind down for the evening, limiting the use of electronic devices near bedtime, keeping the bedroom dark and cool and going to bed and waking up at the same time each day.”

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