Bad sleep may raise risk of this type of heart condition: study

By Stephen Beech via SWNS

Working shifts raise the risk of potentially fatal hardened arteries, according to a new study.

Researchers found that irregular sleeping patterns may increase the likelihood in people over the age of 45 of atherosclerosis - the buildup of fats, cholesterol and other substances in and on the artery walls.

The buildup is called plaque and can cause arteries to narrow, blocking blood flow.

The plaque may burst and create a blood clot that blocks the artery, which could lead to a heart attack or stroke.

Scientists who conducted the new study say that maintaining a consistent sleep pattern may play an important role in preventing such a life-threatening problem.

The study, involving more than 2,000 American adults, showed that variations in sleep duration of more than two hours a night within the same week were tied to developing hardened arteries.

Study lead author Dr. Kelsie Full, of Vanderbilt University Medical Center, said: “This study is one of the first investigations to provide evidence of a connection between irregular sleep duration and irregular sleep timing and atherosclerosis."

The study participants had an average age of 69, and just over half were women.

Between 2010 and 2013, they wore a wrist device that detected when they were asleep and awake, and they also completed a sleep diary for seven consecutive days.

The participants also completed a one-night, in-home sleep study to measure sleep disorders involving breathing, sleep stages, waking after sleep onset and heart rate.

Sleep duration was defined as the total amount of time spent in bed fully asleep, while sleep timing was described as the time a person falls asleep each night.

The greatest irregularity in the number of hours participants slept was a variation of more than two hours within one week.

Those with the greatest irregularity in sleep timing varied the time they fell asleep by more than 90 minutes within one week.

Researchers gauged the presence of plaque in the arteries. Other data evaluated included education, yearly income, work schedule, cigarette and alcohol consumption, physical activity, body mass index (BMI), blood pressure and usual work schedules.

The analysis found participants with irregular sleep durations that varied by more than two hours within a week were 1.4 times more likely to have high coronary artery calcium scores compared to those with more consistent sleep durations.

The score measures the amount of calcified plaque in the arteries, which is the main underlying cause of cardiovascular disease events such as heart attacks and strokes.

Participants with irregular sleep durations that varied by more than two hours within a week were 1.12 times more likely to have carotid plaque and nearly twice as likely to have abnormal results from an ankle brachial index – a test of systemic atherosclerosis and stiffness in the blood vessels, comparing blood pressure at the ankle to blood pressure in the arm.

Participants with more irregular sleep timing, varying more than 90 minutes within a week, were 1.43 times more likely to have high coronary artery calcium scores compared to those with more regular sleep timing, according to the findings published in the Journal of the American Heart Association.

The research team found little evidence linking sleep timing irregularity with other cardiovascular disease markers.

Dr. Fell added: “Maintaining regular sleep schedules and decreasing variability in sleep is an easily adjustable lifestyle behavior that can not only help improve sleep, but also help reduce the cardiovascular risk for aging adults."

The American Heart Association suggests adults should get seven to nine hours of sleep a night because adequate sleep promotes healing, improves brain function and lowers the risk for chronic diseases.

Dr. Fell said the findings support continued research to better understand sleep irregularity and the development of cardiovascular disease risk.