High-density lipoprotein (HDL) is one of the five major groups of lipoproteins, which, in order of sizes, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, which enable lipids like cholesterol and triglycerides to be transported within the water-based bloodstream. In healthy individuals, about thirty percent of blood cholesterol is carried by HDL. Blood tests typically report HDL-C level, i.e. the amount of cholesterol contained in HDL particles.
High-density lipoprotein (HDL), is called the good cholesterol because HDL cholesterol transports the LDL cholesterol out of the bloodstream and prevents it from building up in arteries. Exercise can increase the production of HDL cholesterol.