Despite the widely known benefits of getting enough sleep, the old adage, “You can sleep when you’re dead,” is favored among college kids, workaholics and night owls alike. Now, researchers are once again suggesting we take a second look at how much rest we’re getting, and they’re serious — like a heart attack.

In a new study from the American College of Cardiology, results indicate that folks who suffer from insomnia were 69% more likely to have a heart attack than those without the sleep disorder. And, when using sleep duration as a measure of insomnia, those who slept five hours or less per night had the greatest risk of experiencing a heart attack.

Published in the scientific journal Clinical Cardiology, the study’s researchers conducted a systematic review of existing studies and found a significant association between insomnia and having a heart attack — even after they controlled for age, gender, comorbidities and smoking.

Participants who reported sleeping five hours or less a night were 1.38 times more likely to have a heart attack compared with participants who slept for six hours a night. And the five-hours-a-night crowd were 1.56 times more likely to have a heart attack than those who logged seven to eight hours of shuteye.

Getting too much sleep, however, can be almost as harmful as getting too little. Even sleeping six hours a night, as opposed to the lauded eight, carried a lower heart attack risk compared with folks who slept nine hours a night.

So check in on your own sleep habits. Rest assured, sleep continues to be a critically important factor in our overall health.