sleeping coupleYou probably already know that not getting enough sleep is bad for you. When you don’t sleep enough, you can feel the results for yourself: you’re groggy, less focused, and probably spending most of your day wishing you were back in bed. But did you know that getting too much sleep, or even just poor quality sleep, could be just as bad for your health? And even worse, bad for your heart?

A new study published in the journal Arteriosclerosis, Thrombosis and Vascular Biology has found a profound link between the amount and quality of your sleep and cardiovascular disease. According to researchers at the Center for Cohort Studies at Kangbuk Samsung Hospital and Sungkyunkwan University School of Medicine in Seoul, South Korea, getting just the right amount of sleep, as well as good-quality sleep, is more important to heart health than we have previously thought. Improper sleep habits could be putting you at a higher risk for early signs of heart disease, even at a relatively young age.

Researchers studied more than 47,000 men and women with an average age of around 41. The team first surveyed them about how long and how well they slept. Then they measured a couple key indicators of cardiovascular health.

Calcium buildup and arterial stiffness are two important warning signs of heart disease that cardiologists can test for. Early coronary lesions can be detected by measuring the amount of calcium in the arteries of the heart. Stiffness of arteries can be measured by the speed of blood as it moves through the arteries.

After surveying and testing their volunteers, they found that adults who slept fewer than five hours a night had 50 percent more calcium in their coronary arteries than those who slept seven hours. More surprisingly, they found that sleeping too much produced even worse results. Those who slept nine hours or more a night had 70 percent more coronary calcium compared to those who slept seven hours.

Sleep quality was also found to play a key factor in their results. For those adults who reported poor sleep quality, they were found to have 20 percent more calcium buildup in their arteries than those who reported good quality sleep. Similar patterns emerged when they measured arterial stiffness of poor quality sleepers vs good quality sleepers.

The findings suggest that poor sleep quality, too much sleep, and too little sleep all affect heart health in a profound way. To see such an influence on the test subjects blood vessels so early in life is an important finding that doctors and health care providers alike need to be make aware of.

Dr. Yoosoo Chang, co-lead author of the study says, the best heart health was found in adults who slept, on average, about seven hours a night and reported good sleep quality.

This study does not necessarily prove that sleep problems cause heart problems, let alone explain how. Follow up research will be necessary to determine how much of an impact sleep has on real outcomes of heart health over time. Researchers will need to look at a lot more than arterial stiffness and calcium buildup, including hormones, metabolic factors produced by sleep and chemical changes in the body during sleep that can increase blood pressure in order to really understand the mechanisms at play.

This study should be a heads-up for health care providers and cardiologists when assessing cardiovascular risk and overall health status. Sleep habits might need to become a much more common discussion with patients when they come in for their yearly check up.