Sleeping between 6 and 9 hours nightly appears optimum for heart health, according to a University of Colorado Boulder study published in the Journal of the American College of Cardiology.

People who have a genetically elevated risk for heart disease can reduce their risk of heart attack by 18 percent by getting adequate sleep.

Scientists are still studying how sleep affects heart health, but trying to get more sleep if you sleep too little—and seeing your doctor to rule out underlying health issues if you are a chronic long sleeper—could improve your heart attack risk.



You can ride lots, eat well, avoid cigarettes, be built like a World Tour pro, and have no genetic predisposition for heart disease, but if you skimp on your sleep—or get excessive amounts of it—your heart may still be at risk, according to a new University of Colorado Boulder study of nearly a half-million people published in the Journal of the American College of Cardiology.

In the study, researchers at the Massachusetts General Hospital and the University of Manchester analyzed the genetic information, self-reported sleep habits, and medical records of 461,000 U.K. Biobank participants ranging in age from 40 to 69 who had never had a heart attack, then followed them for seven years.



Those who slept fewer than six hours nightly were 20 percent more likely to have a heart attack during the study period than those who snoozed for 7 to 8 hours a night. As for those who logged longer than nine hours? They were 34 percent more likely to experience a heart attack than the middle-ground sleepers.

The risk for heart attack increased the farther people fell outside of the 6 to 9-hour optimum range. Those clocking just five hours of shuteye per night had a 52 percent higher risk than those who got 7 to 8 hours a night. Long sleepers who slumbered 10 hours each night were twice as likely to have a heart attack.

The risk remained even after the researchers took into account 30 other common cardiovascular risk factors, including habitual exercise levels, mental health, body composition, and socioeconomic status.

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What’s more, getting the optimal amount of sleep also lessened the heart attack risk for those with a family history for heart disease: Among those with a genetic predisposition, sleeping between 6 and 9 hours a night reduced their risk of heart attack by 18 percent.

“It’s kind of a hopeful message, that regardless of what your inherited risk for heart attack is, sleeping a healthy amount may cut that risk just like eating a healthy diet, not smoking, and other lifestyle approaches can,” said lead author Iyas Daghlas, a medical student at Harvard, in a press release.

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Exactly how short or long sleep elevates heart attack risk isn’t 100 percent understood. However, a tall body of research shows that chronic sleep deprivation can wreak havoc on the body, increasing systemic inflammation, disrupting normal appetite and satiety hormones, and hindering immunity, making you more susceptible to a host of diseases including obesity, diabetes, heart disease, and even early death.



“We think that extending sleep will benefit heart health, and there are ongoing studies examining exactly that,” senior author Celine Vetter, an assistant professor of integrative physiology, told Bicycling.



As for sleeping too much? That may also boost inflammation in your body, which is also associated with cardiovascular disease. But what to do if you find yourself on the “oversleeping” end of the spectrum is less clear, Vetter said. (For one, there are not a whole lot of people who do it—only about 7 percent of people in the U.S. regularly log 9 or more hours, she said).

Sleep expert Christopher Winter, M.D., president of Charlottesville Neurology and Sleep Medicine and author The Sleep Solution: Why Your Sleep Is Broken and How To Fix It believes that genetics, as well as underlying (and maybe undetected) health issues could be at play in so called long sleepers.



Some folks may just genetically need more than the average amount of sleep, Winter said. In that case, it’s likely not hinting at anything more sinister.

But in other cases, their need for sleep may be reflecting an undiagnosed health problem like depression or sleep apnea, which disrupts their sleep quality, making them compensate with more quantity. In that case, seeing a doctor would be in order. Other factors, like medication side effects or a difficult sleep schedule related to shift work may also be at play, he said.

In those cases, Winter says it’s worth scheduling an appointment with your doctor to talk about your sleep issues, determine the underlying causes, and find ways to get on a better sleep schedule—doing so could potentially improve your health and lower your heart attack risk.

Selene Yeager “The Fit Chick” Selene Yeager is a top-selling professional health and fitness writer who lives what she writes as a NASM certified personal trainer, USA Cycling certified coach, Pn1 certified nutrition coach, pro licensed off road racer, and All-American Ironman triathlete.

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