Adults who get too much or too little sleep may have the beginnings of “hardening” of the arteries, which can be an early sign of heart disease, according to a new study.
“Many people, up to one-third or one-fourth of the general population, suffer from inadequate sleep – either insufficient duration or poor quality of sleep,” said co-lead author Dr. Chan-Won Kim of Kangbuk Samsung Hospital of Sungkyunkwan University School of Medicine in Seoul, South Korea.
Several studies have linked inadequate sleep with an increased risk of heart attack and stroke, but other conditions like depression or obesity could influence this association, Kim told Reuters Health.
“In contrast, we studied if sleep of inadequate duration or quality would be linked to early markers of heart disease in asymptomatic healthy adults free of heart disease,” Kim said.
For the study, more than 47,000 men and women, age 42 on average, completed a sleep questionnaire and had tests to detect lesions of calcium and plaque in the artery leading to the heart, an early sign of disease, and arterial stiffness in the leg, a sign of vascular aging.
According to their questionnaires, the participants’ average sleep duration was 6.4 hours per night, and about 84% said their sleep quality was “good.” Researchers considered those who got five hours or less per night to be “short” sleepers, and those who got nine or more hours to be “long” sleepers.
Short sleepers had 50% more calcium in their coronary arteries than those who slept for seven hours per night. Long sleepers had 70% more calcium than those who slept seven hours.
“The calcium score obtained by computerized tomography scan is a very good measure of calcium buildup in the coronary arteries reflecting coronary atherosclerosis,” Kim said. “The higher the coronary calcium score, the greater the risks of a heart attack.”
Those who reported poor sleep quality also tended to have more coronary calcium and more arterial stiffness.
“Adults with poor sleep quality have stiffer arteries than those who sleep seven hours a day or had good sleep quality,” co-lead author Dr. Yoosoo Chang of the Center for Cohort Studies at Kangbuk Samsun Hospital said.
Short sleepers were more likely than others to be older, have depression, type 2 diabetes or to be smokers.
“It is still not clear if inadequate sleep is the cause or the consequence of ill health,” but good sleep hygiene, including avoiding electronic media at bedtime, should be part of a healthy lifestyle, Kim said.
