Too much or too littlesleepcan magnify heart attack risk.
Those who slept fewer than six hours were 20% more likely to have a heart attack.
Those who slept more than nine hours were 34% more likely to have a heart attack.
Want to cut your risk of having a heart attack by as much as a third? Get some zzz’s. But not too many.
That’s the takeaway from new Ƶ Boulder research suggesting sleep—such asdiet and exercise—can play a key role in promoting cardiovascular health.
“Just as working out and eating healthy can reduce your risk of heart disease, sleep can too,” says sleep researcher Celine Vetter, an assistant professor of Integrative Physiology.
In a study, published in the Journal of the American College of Cardiology, Vetter found that even if you are a healthy non-smoker who exercises and has no genetic predisposition to heart disease, skimping on sleep—or getting too much of it—can significantly boost your risk of heart attack.
The magic number for heart-healthy slumber, the study found, lies somewhere between six and nine hours nightly.
For the study, Vetter and co-authors at the Massachusetts General Hospital and the University of Manchester, analyzed the genetic information, self-reported sleep habits and medical records of 461,000 people ages 40 to 69 who had never had a heart attack, then followed them for seven years.
Compared to those who slept six to nine hours per night, those who slept fewer than six hours were 20% more likely to have a heart attack. Those who slept more than nine hours were 34% more likely.
The farther people fell outside that ideal range, the more their risk increased. For instance, people who slept five hours per night had a 52% higher risk of heart attack than those who slept seven to eight hours, while those who slept 10 hours nightly were twice as likely to have one.
The upside: Even study subjects with a genetic predisposition to heart disease were able to counteract that risk by as much as 18% by getting the right amount of sleep.
“This study 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,” said Vetter.
The looming question: What exactly does lack of sleep, or too much of it, do to the heart? More studies are underway, but earlier research has offered some hints.
Sleeping too little can damage the lining of the arteries and lead to poor dietary choices and ill-timed eating – all bad things for the ticker. Sleeping too much, on the other hand, may boost inflammation throughout the body, fueling a host of health problems.
Vetter’s advice for hitting that sleep sweet spot: Shoot for seven to eight hours of quality sleep nightly.