It has previously been established through epidemiological studies that people who sleep less than they should have a higher risk of contracting cardiovascular diseases, a higher risk of mortality from cardiovascular diseases, and a higher overall mortality over a set time span.

Cardiovascular diseases are known to be linked to both metabolism and the immune system. Sleep loss has been demonstrated to cause low-grade inflammatory state in the body, and this may contribute to the higher risk of disease. Carbohydrate metabolism has also been found to alter in sleep deficiency in ways that resemble type 2 diabetes.

The study examined the impact of cumulative sleep deprivation on cholesterol metabolism in terms of both gene expression and blood lipoprotein levels. With state-of-the-art methods, a small blood sample can simultaneously yield information about the activation of all genes as well as the amounts of hundreds of different metabolites. This means it is possible to seek new regulating factors and metabolic pathways which participate in a particular function of the body.

The study established that the genes which participate in the regulation of cholesterol transport are less active in persons suffering from sleep loss than with those getting sufficient sleep. This was found both in the laboratory-induced sleep loss experiment and on the population level. Study also found increased expression in pathways involved in inflammatory responses.

While analysing the different metabolites, the researchers found that in the population-level data, persons suffering from sleep loss had fewer high-density HDL lipoproteins, commonly known as the good cholesterol transport proteins, than persons who slept sufficiently.

Together with other risk factors, these results help explain the higher risk of cardiovascular disease observed in sleep-deprived people and help understand the mechanisms through which lack of sleep increases this risk.

The results highlight the health impact of good sleep. The researchers emphasize that health education should focus on the significance of good, sufficient sleep in preventing common diseases, in addition to healthy food and exercise. Even a small reduction in illnesses, or even postponing the onset of an illness, would result in significant cost savings for society at large.