The new study from the University of Colorado Boulder published in the Journal of the American College of Cardiology included nearly half a million people and found that for those at high genetic risk for heart attack, sleeping between 6 and 9 hours nightly can offset it.
Senior author Celine Vetter, an assistant professor of Integrative Physiology, spoke about the study. “This provides some of the strongest proof yet that sleep duration is a key factor when it comes to heart health, and this holds true for everyone.”
For the seven-year study, Vetter and co-authors collected and analyzed the genetic information, sleep habits, and medical records of 461,000 UK biobank participants aged 40 to 69. All participants had never experienced a heart attack.
They found that those who slept fewer than six hours a night were 20 percent more likely to experience a heart attack compared to those who slept for six-to-nine hours a night. On the opposite end of the spectrum, those who slept more than nine hours were 34 percent more likely to have a heart attack.
Not getting enough sleep can impact the lining of the arteries, or endothelium, and impact bone marrow development of inflammatory cells. It can also lead to poor dietary choices, which can affect weight. Sleeping too much could boost inflammation in the body. All of these side effects of sleep are linked to cardiovascular disease.
After all of the information was analyzed in people who had a genetic predisposition to heart disease, they found that sleeping between six and nine hours a night cut their risk of having a 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 who was not involved in the study.
Risk for Heart Attack Increased
This was the first study of its kind to show that the farther people fell outside of the six-to-nine hour recommended sleep range, the more their risk for heart attack increased. For example, people who slept five hours per night had a 52 percent higher risk of heart attack, while those who slept 10 hours nightly were twice as likely to have one.
To look at the participant’s genetic profiles, researchers used a method called Mendelian randomization to determine whether those who were genetically predisposed to short sleep were more likely to have heart attacks. Twenty-seven genetic variants have been associated with short sleep.
They found similar patterns that emerged and found that genetically influenced short sleep duration was a risk factor for heart attack.
Vetter explained, “This gives us even more confidence that there is a causal relationship here that it is sleep duration, not something else, influencing heart health.”
The authors of the study hope the new information will increase awareness about the relationship between sleep duration and its heart-health benefits. Many people only think about exercise and healthy eating, but sleep duration can also greatly help to reduce the risk of heart disease.