Researchers at the Center for Cohort Studies at Kangbuk Samsung Hospital and Sungkyunkwan University School of Medicine in Seoul, South Korea, studied more than 47,000 young and middle-aged men and women, according to a story on National Public Radio.
They asked participants about their sleep habits and then conducted tests to measure cardiovascular health, including looking at calcium buildup in the arteries and measuring the stiffness of arteries. These two factors are important warning signs of oncoming heart disease.
Adults who slept fewer than five hours a night had 50% more calcium in their coronary arteries than those who slept seven hours, researchers found. But was more sleep better? Apparently not. Those who slept nine hours or more a night had 70% more calcium in their coronary arteries than those who slept only seven hours.
The quality of sleep also mattered. Those who reported sleeping poorly had 20% more arterial calcium buildup than those who reported sleeping well. In addition, researchers found similar results when they looked at arterial stiffness, NPR reports.
Overall, the best heart health was discovered in adults who slept well for an average of about seven hours a night.