Doctors actively monitor the concentrations of LDL and HDL in their patient's blood because different concentrations of both are associated with the risk of heart disease. High concentrations of LDL increases the risk of heart disease since it leads to the building up of plague in the arteries. This build up leads to the arteries hardening which then can lead to a heart attack and a stroke. However, high concentrations of HDL can decrease the risk of heart disease due to its function being to carry cholesterol back to the liver. This then means that plague won't be able to build up in the arteries which makes HDL a good promoter of good cardiovascular health. So the levels of LDL and HDL in the blood are measured to determine if there is more
