BERKELEY, Calif. — Can’t get a good night’s sleep? For many years, researchers have known that there is an association between interrupted sleep and an increased risk of cardiovascular disease. The mechanism that causes this increased risk has eluded scientists — until now. Researchers from the University of California at Berkeley say that interrupted sleep causes an inflammatory response that can cause atherosclerosis (the clogging of arteries by cholesterol plaque) to worsen and increases the risk of stroke.
The research team recruited 1,600 adults to participate in sleep studies so they could monitor their inflammatory pathways while they slept. Two types of tools to measure sleep disruptions were used: a lab-based polysomnography (used over a single night) and actigraphy (a movement detector that’s used over multiple nights).
The team sought to determine how sleep disruptions affect the levels of two types of white blood cells that contribute to the inflammatory response of the body: neutrophils and monocytes. They also looked at the levels of plaque-causing-calcium deposits in the coronary arteries.
Using the measurements taken from the two sleep-study modalities, the study shows a relationship between movements during sleep and an increase in neutrophil and calcium measurements. The increase is not seen in monocyte levels, however. Thus, researchers conclude that poor sleep leads to an increase in neutrophil, which leads to an increase in calcium deposits and worsened atherosclerosis.
The actigraphy measurements demonstrate this relationship more clearly than the polysomnography. Researchers think this is because they only have one night’s worth of polysomnography data versus an entire week’s worth of actigraphy data.
“Improving sleep may offer a novel way to reduce inflammation and thus reduce the risk of atherosclerosis,” explains lead author Matthew Walker, a Professor of Psychology at Berkeley, in a media release.
“These findings may help inform public health guidelines that seek to increase the continuity of sleep as a way to improve health and decrease the burden of heart disease on society,” he concludes.
The study is published in PLOS Biology.