The researchers found that extreme sleep durations and poor quality of sleep were linked with elevated coronary artery calcium levels and arterial stiffness.
The study, published in the journal Arteriosclerosis, Thrombosis and Vascular Biology, found getting too much sleep, too little sleep or poor quality sleep was associated with raised levels of calcium in the coronary arteries and arterial stiffness.
"Inadequate sleep is a common problem and a likely source of poor health, including visible signs of disease, such as heart attack," reports co-lead author Dr. Chan-Won Kim, a clinical associate professor at Kangbuk Samsun Hospital, Sungkyunkwan University School of Medicine in Seoul, South Korea.
Several previous studies have demonstrated that sleeping for too long or not long enough is linked to an increased risk of cardiovascular disease (CVD) events. However, the association between sleep and the risk of CVD is not fully understood.
To investigate, a team of researchers set out to evaluate the cardiovascular health of individuals alongside the quality of how they slept.
A total of 47,309 young and middle-aged adults had their sleep duration and sleep quality assessed with a sleep questionnaire. Each participant also underwent a health examination to measure coronary artery calcium and arterial stiffness, two subclinical measures of CVD.
The presence of calcium in the coronary arteries indicated the presence of early coronary lesions. The researchers measured arterial stiffness by observing the speed of the pulse between the arteries of the upper arm and the ankle.
Inadequate sleep was linked to raised levels of coronary artery calcium. Participants who slept 5 or fewer hours a day had 50% more coronary artery calcium than those who reported sleeping 7 hours a day.
Likewise, participants who reported sleeping 9 or more hours a day had more than 70% more coronary artery calcium compared with those who slept 7 hours a day. Participants reporting poor quality of sleep had over 20% more coronary artery calcium than those who reported good sleep quality.
Doctors 'may need to assess sleep quality when evaluating cardiovascular risk'
The researchers uncovered similar findings when assessing arterial stiffness.
"Adults with poor sleep quality have stiffer arteries than those who sleep 7 hours a day or had good sleep quality," states co-lead author Dr. Yoosoo Chang, an associate professor at Kangbuk Samsun Hospital. "Overall, we saw the lowest levels of vascular disease in adults sleeping 7 hours a day and reporting good sleep quality."
The researchers write that several mechanisms could be behind their findings. Inadequate sleep is associated with several cardiovascular health problems such as elevated blood pressure and impaired glucose metabolism.
Previous research from the team also demonstrated that not sleeping long enough and poor sleep quality are associated with an increased risk of nonalcoholic fatty liver disease - a condition that indicates a form of fat deposition linked with CVD.
They acknowledge that the study is limited by relying on self-reporting to measure sleep duration, and that inadequate sleep could also simply reflect other underlying health issues. Despite these limitations, the researchers believe their findings highlight how important sleep is for maintaining cardiovascular health.
"For doctors, it might be necessary to assess patients' sleep quality when they evaluate the cardiovascular risk and the health status of men and women," Dr. Kim concludes.
Recently, Medical News Today reported on a study demonstrating that a lack of sleep could increase the risk of catching the common cold.