HDL (high-density lipoprotein) cholesterol is a lipid protein complex found in human blood circulation. HDL molecules are produced by liver.
HDL removes bad cholesterol (also known as LDL, ie low-density lipoprotein) from the blood circulation and from the internal layer of artery and dumps it into the liver, where it’s broken down and finally excreted from the body. By this way HDL cholesterol helps our body to get rid of the bad cholesterol. This is why HDL is also called good cholesterol.
LDL or the bad cholesterol on the other hand dumps cholesterol in the inner layer of the arteries and called hardening and narrowing of the arteries. Once the arteries become hard, the elasticity of these arteries decrease and at times of heavy physical exertion blood supply (and oxygen supply) may not be adequate to the heart and can precipitate a heart attack.
Similarly, narrowing of arteries can decrease blood and oxygen supply to the brain and can give rise to a stroke. There are many others complications that can happen due to atherosclerois, which we are not discusssing here. Here comes the role of HDL cholesterol’s which dont allow dumping of bad (LDL) cholesterol undereath the arteries and therefore reduce the risk of having dangerous aftermaths like stroke, heart attack etc.
HDL cholesterol levels should be higher than 40mg/dl. Cigarette smoking decreases blood HDL cholesterol levels, hence increases the risk of hardening of arteries. Regular exercises help to raise the HDL levels.