Sleep habits could indicate early warning for heart disease

Chronic short sleep duration is associated with an increased susceptibility to heart disease, in large part due to increased inflammatory burden and endothelial dysfunction, and researchers from Cornell University in Ithaca, New York, may have identified why this is, a discovery that could allow practitioners to identify patients who might need to change their habits before they develop disease, according to a new study in the journal Experimental Physiology.

The researchers studied 24 sedentary middle-aged adults, 12 with a normal nightly sleep duration of greater than seven hours per night, and 12 with a short nightly sleep duration of less than seven hours per night. All subjects were non‐smokers, normolipidemic, non‐medicated, and free of overt cardiovascular disease, according to the study abstract.

Study participants were asked to complete a questionnaire designed to accurately estimate average nightly sleep and a small amount of blood was taken from each subject after an overnight fast. MicroRNAs, molecules that influence whether or not a gene is expressed, 125a, 126, and 146a were extracted from the blood and measured.

Circulating levels of microRNA 125a, 126, and 146a were significantly lower in those who regularly slept less than seven hours per night when compared to the normal sleep group, researchers found.

These molecules play a key role in regulating vascular health and levels are now recognized to be sensitive and specific biomarkers of cardiovascular health, inflammation, and disease, researchers said. A lowered level of these molecules is associated with heart disease, so they could be used as a biomarker to determine who is more susceptible to disease, according to Jamie Hijmans, PhD, the lead author of the study.

"The link between insufficient sleep and cardiovascular disease may be due, in part, to changes in microRNAs,” he said in a statement released by the university. “These findings suggest there may be a fingerprint associated with a person's sleep habits, and that fluctuations in microRNA levels may serve as a warning or guide to disease stage and progression."