Sleeping to Protect Your Heart

Sleep deprivation has previously been shown to be a risk factor for many disorders with metabolic disturbances, including heart disease, diabetes, and obesity. How the loss of sleep promotes heart attacks has not been elucidated. Researchers from the University of Helsinki recently conducted a study where they analyzed this question in nearly 3,000 human subjects both in a controlled experimental environment and in the community. For the controlled experimental sleep restriction, they recruited 14 individuals to undergo five consecutive days of four hours of sleep restriction per night alongside seven individuals who slept eight hours per night. For the second study, conducted to reflect more of real life settings and long-term sleep deprivation, the researches recruited 2,739 participants and determined their average level of sleep sufficiency or deprivation. In both groups, blood was drawn to analyze the expression of inflammatory genes and proteins related to lipid metabolism. The researchers observed increased expression of pro-inflammatory genes in both studies. In the large cohort study, they also observed that sleep deprived individuals have decreased levels of HDL cholesterol, which helps remove the LDL cholesterol. Although they found decreased levels of LDL in the short-term sleep deprivation group from the controlled experimental study, this is likely caused by a shock inflammatory response called acute-phase response as shown in previous scientific studies. As chronic inflammation and low HDL have both been shown to promote build-up of blood vessel blockages, this human-focused study provides insights into how sleep deprivation can increase one’s risk for cardiovascular disease.