Could Poor Sleep Increase Risk of Heart Disease?

Not getting your proper sleep? You may be at a greater risk for early signs of heart disease, according to a new study.

Researchers found adults who reported getting 7 hours of good-quality sleep appeared to have the lowest levels of vascular disease among study participants.

“We found that sleep duration had a U-shaped association with two early markers of vascular disease, irrespective of traditional risk factors, such as hypertension, diabetes, or hypercholesterolemia in healthy adults without major disease,” says co-lead study author Chan-Won Kim, MD, clinical associate professor in the Center for Cohort Studies at Kangbuk Samsun Hospital, Sungkyunkwan University School of Medicine in Seoul, South Korea.
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Kim and his colleagues analyzed data from more than 47,000 young and middle-aged adults to determine the association between sleep duration and sleep quality with coronary artery calcification and with arterial stiffness.

Study participants completed a sleep questionnaire reporting sleep duration and quality, while researchers used the presence of calcium in the coronary arteries to detect early coronary lesions and assessed arterial stiffness by measuring the velocity of the pulse wave between the arteries in the upper arm and ankle.

After measuring coronary calcium, they found:

• Adults who sleep 5 or fewer hours a day have 50% more calcium in their coronary arteries than those who sleep 7 hours a day.

• Those who sleep 9 or more hours a day have more than 70% more coronary calcium than those who sleep 7 hours.

• Adults who reported poor sleep quality had more than 20% more coronary calcium than those who reported good sleep quality.

“Our results underscore the importance of adequate sleep quantity and quality to maintain cardiovascular health and support the need for considering subjects with extreme duration or poor subjective quality of sleep at high risk for (cardiovascular disease),” the authors wrote.

While the study did not identify any causation because it was only observational in nature, Kim suggests several mechanisms may account for the U-shaped association of sleep duration with coronary calcification and with arterial stiffness.

“Low-grade inflammation, insulin resistance, or higher blood pressure attributed to sleep deprivation may mediate the association between sleep deprivation and increased levels of coronary calcium,” he says. “And sleep fragmentation linked to too much sleep may activate sympathetic nervous system, potentially affecting cardiovascular health.”

He and his colleagues note further research is needed to confirm these findings and to gain more insight into the relationship between sleep quality and cardiovascular health.

“Both acute and chronic effects of inadequate sleep may play a synergistic role in atherosclerotic process and arterial stiffness,” Kim says. “We have plans to investigate the effects of inadequate sleep on health using longitudinal design and also determinants of inadequate sleep in healthy adults.”

—Colleen Mullarkey

Reference

Kim CW, Chang Y, Zhao D, Cainzos-Achirica M, Ryu S, Jung HS, et al. Sleep duration, sleep quality, and markers of subclinical arterial disease in healthy men and women. Arterioscler Thromb Vasc Biol. 2015 Sep 10. [Epub ahead of print].