High Density Lipoprotein (HDL) is known as good cholesterol because it helps to protect the arteries from the process of atherosclerosis where the arteries get blocked and leads to various heart diseases. HDL performs this function by extracting the cholesterol particles from the walls of the arteries and transports them to the liver from where the bile disposes them off. HDL also helps to interfere, LDL cholesterol accumulation in the walls of the arteries. The risk of heart attacks and atherosclerosis are strongly related to the levels of HDL cholesterol in the body. High levels of this good cholesterol are associated with low risk whereas low levels of this cholesterol are associated with high risk. It is quite a possibility that very high and very low levels of HDL cholesterol may run into families and thus the families having low level of HDL have higher chances of suffering from heart attacks as compared to general population.  On the other hand, for the families having high level of HDL, the frequency of heart attacks is low and they even tend to have a longer life. HDL cholesterol levels are influenced by factors associated with life style and other conditions. This good cholesterol levels are low in people who smoke, are inactive and overweight, suffers from type 2 diabetes and consume lots of sweets.