ProLipid

High cholesterol can lead to atherosclerosis, a process in which the build up of plaque inside the artery walls leads to the hardening and narrowing of blood vessels. The blood flow through these narrowed arteries is reduced.

If the coronary arteries that supply the heart are affected, it can cause heart pain and feelings of constriction such as angina pectoris, especially in times of physical or psychological stress.

... and HDL is good.

As you can see in this article, LDL (or HDL) cholesterol are actually indicators of how many LDL and HDL 'particles' are present in the blood.

This is the function of LDL and HDL particles:

Professor Law and his colleagues of the University of London searched scientific literature in order to calculate the effect of LDL cholesterol reduction on the risk of a heart attack. Given a pre-treatment LDL cholesterol level of 190 mg/dL (4.8 mmol/L), which was the average value of all the patients investigated, they discovered the following: