• Having an irregular sleep schedule can negatively impact your heart health, new study finds.
  • This evidence adds to the growing body of research that proves maintaining a good sleep hygiene is good for your overall health.

For years, health experts have stressed the importance of getting a good night’s sleep for your overall health. But a new study found having irregular sleep patterns can be rough on your heart in particular.

The study, which was published in the Journal of the American Heart Association, analyzed data from more than 2,000 adults from across the country with the average age of 69. From 2010 to 2013, the study participants wore a device around their wrist that tracked when they were asleep and awake, and they also filled out a sleep diary for seven straight days. Participants also did a one-night, in-home sleep study to look at their breathing, sleep stages, waking after they went to sleep, and heart rate.

Overall, the biggest irregularity in the number of hours study participants slept was more than two hours in one week, and those with the biggest irregularities varied the time they fell asleep by more than 90 minutes in one week.

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The researchers conducted a slew of tests to look for buildup of plaque in the arteries (a condition known as atherosclerosis, which can cause a heart attack, stroke, or blood clot) and found that people with irregular sleep patterns were more likely to have higher levels of plaque compared to those with more consistent sleep schedules. Specifically, those whose sleep durations varied by more than two hours in a week were 1.4 times more likely to have high coronary artery calcium scores (which measures the amount of calcified plaque in the arteries, the main underlying cause of cardiovascular events such as heart attacks and strokes) compared to those who had more consistent sleep durations.

People with irregular sleep durations that varied by more than two hours a week were 1.12 times more likely to have carotid plaque (plaque in arteries that deliver blood to your brain). Those who had more irregular sleep timing (i.e. they mixed up when they went to bed and when they woke up) were 1.43 times more likely to have high coronary artery plaque compared to those who had sleep timing that varied by 30 minutes or less within a week.

The researchers concluded that regular sleep patterns could be a “modifiable” factor in helping people to reduce their risk of atherosclerosis. But…why? Here’s what you need to know.

Why might irregular sleep patterns raise your risk of heart disease?

It’s important to note that heart disease—including atherosclerosis—is a complicated condition that can have many causes. At the same time, this particular study found a link between irregular sleep and atherosclerosis, but didn’t show that having irregular sleep patterns actually causes atherosclerosis. “Irregular sleep may also indicate irregular lifestyle habits such as irregular timing of food, poor food habits, and diet that were not taken into consideration,” points out Jag Sunderram, M.D., interim chief in the Division of Pulmonary and Critical Care Medicine at the Rutgers Robert Wood Johnson Medical School.

“It is likely that the link is multifactorial and sleep may play an important role of many factors,” says lead study author Kelsie M. Full, Ph.D., M.P.H., assistant professor of medicine at Vanderbilt University Medical Center.

Still, this isn’t the first study to make the connection between sleep issues and heart disease.

“These findings support a growing body of research that show the health benefits of regular sleep patterns—going to bed at the same time and getting out of bed at the same time,” says Holly S. Andersen, M.D., attending cardiologist and an associate professor of clinical medicine at the New York-Presbyterian Hospital, Weill Cornell Medical Center. “The body likes a schedule.”

A study published in the Journal of the American College of Cardiology in 2020 analyzed data from nearly 2,000 men and women and also found that irregular sleep patterns increased the risk of heart attack, stroke, and other cardiovascular events. At the start of the study, no participants had cardiovascular disease. After five years, 111 had some cardiovascular issue, including heart attack, stroke and even death from a cardiac-related issue. The researchers found that people with irregular sleep schedules were nearly twice as likely to develop cardiovascular disease as those with more regular sleep patterns.

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Research has also connected inconsistent sleep with poor heart health. The Centers for Disease Control and Prevention (CDC) specifically warns that adults who sleep less than the recommended seven hours a night are more likely to have health problems, including heart attack.

Researchers are still sorting out the reason for this, but there seems to be a few factors at play. “Chronic fatigue from sleep deprivation may lead to decreased physical activity, poor dietary choices, overeating due to low energy, and potentially weight gain,” says Thomas Boyden, M.D., Corewell Health medical director for preventive cardiology and cardiac rehabilitation. Those can lead to a slew of health conditions that can then influence your heart health, he says.

One is that lack of sleep and inconsistent sleep can keep your blood pressure up for a longer period of time (your blood pressure goes down when you have normal sleep). High blood pressure is one of the leading causes of heart disease and stroke.

Research has also found that getting good sleep may help some people with type 2 diabetes improve blood sugar management and lower the risk of damage to the blood vessels that can come from a build-up of sugar in the blood. Lack of sleep and irregular sleep can also lead to unhealthy weight gain and obesity, which raises the risk of heart disease.

Dr. Andersen says that it’s “possible” that something else may explain the link between irregular sleep patterns and a higher risk of heart disease, like unhealthy lifestyle choices, but unlikely. “There is much evidence to support that going to bed and getting up at the same time can be a very healthy practice,” she says. “Sleep is made up of different stages including REM or dream sleep. Interfering with these patterns can trigger unhealthy responses in the body for the heart and for memory and cognition.”

What is atherosclerosis?

Atherosclerosis is a condition that develops when a sticky substance called plaque builds up inside your arteries, according to the National Institute of Health (NIH). About half of Americans between the ages of 45 and 84 have atherosclerosis and don’t know it, the NIH says, and diseases linked to atherosclerosis are the leading cause of death in the country.

Atherosclerosis develops slowly as cholesterol, fat, blood cells and other substances in your blood form plaque, the NIH explains. As plaque build up, it causes your arteries to narrow and reduces the supply of oxygen-rich blood to organs in your body.

Symptoms of atherosclerosis can vary, but the NIH says they may include:

  • Chest pain
  • Cold sweats
  • Dizziness
  • Extreme fatigue
  • Heart palpitations
  • Shortness of breath
  • Nausea
  • Cramping in the legs
  • Problems with thinking and memory
  • Weakness or numbness on one side of the body
  • Severe pain after meals
  • Weight loss
  • Diarrhea
  • Erectile dysfunction

How to maximize sleep for your heart health

Again, heart disease is a complicated condition and it’s unlikely that irregular sleep alone will cause atherosclerosis. However, if you can, experts say it’s not the worst idea to try to maintain a consistent sleep schedule, even on the weekends. “Sleeping in on the weekends may feel good and may reduce stress for many of us—but a lifestyle that supports a daily routine with good sleep is superior,” Dr. Andersen says.

“In general, avoiding extreme variations is the key,” Full says.

Also consider this, per Dr. Sunderram: “Sleeping in on weekends is more likely due to chronic sleep deprivation during the week.”

But, if you really love sleeping in on weekends, the data doesn’t definitively say that you need to give it up or your heart health will be screwed. “Potentially, sleeping in for more than 60 minutes than what someone is normally doing during the week could increase risk,” says Jim Liu, M.D., a cardiologist at The Ohio State University Wexner Medical Center. “However, I wouldn’t be too concerned about that right now. There’s a lot that goes into irregular sleep duration and this would have to be studied more before making any firm conclusions about sleep duration regularity and cardiovascular health.”

Keep in mind too, that it’s not a good idea to stay up late during the week and then hope to make up for it on the weekends. “Sleeping in on the weekends may not overcome the deleterious effects of sleep irregularity and decreased sleep duration during the week,” Dr. Boyden says. “The long-term effects of the sleep irregularity and decreased sleep duration will likely continue to have cardiovascular complications even in the setting of better sleep on the weekends.”

In general, it’s good to try to be somewhat consistent with your sleep patterns. “This is provocative in that, as the authors point out, it identifies a readily modifiable lifestyle parameter that could impact one’s cardiovascular risks,” says Devin Kehl, M.D., a non-invasive cardiologist at Providence Saint John’s Health Center in Santa Monica, Calif.

If you’re not sleeping as well as you’d like and it’s leading to sleep irregularity, Dr. Boyden recommends working on your sleep hygiene. According to the CDC, that can include:

  • Sticking to a regular sleep schedule
  • Getting enough natural light, especially earlier in the day
  • Getting enough physical activity during the day
  • Avoiding artificial light, especially within a few hours of bedtime
  • Avoiding eating or drinking within a few hours of bedtime
  • Keeping your bedroom cool, dark, and quiet

“Sleep is essential to our overall health and well-being,” Full says. “It’s important to do what you can to create a healthy and realistic sleep routine that works for you. If you are still having problems with your sleep after this, you should try talking to your health care provider.”

From: Prevention US
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Korin Miller
Korin Miller is a freelance writer specializing in general wellness, sexual health and relationships, and lifestyle trends, with work appearing in Men’s Health, Women’s Health, Self, Glamour, and more. She has a master’s degree from American University, lives by the beach, and hopes to own a teacup pig and taco truck one day.