Cholesterol levels in humans vary with the age of the individual, his or her genetic factors, lifestyle and diet. It is recommended that adults over the age of 20 have a cholesterol level check every five years. A buildup of cholesterol in the bloodstream can lead to serious problems with the cardiovascular system including blocked arteries and even heart failure. Understanding the normal levels of cholesterol and what the numbers represent is very helpful when managing one's health.Good And Bad CholesterolCholesterol is actually a necessary component of our cells. The cell membranes are constructed of cholesterol along with other compounds. Cholesterol is therefore a required part of the diet. Unfortunately many people have an excess of cholesterol in their system. Too much cholesterol can concentrate in arteries and even within the heart chambers.There are two types of cholesterol. The first is known as LDL, which stands for low-density lipoprotein. A lipoprotein will attach itself to cholesterol units and transport them to the cells. Cholesterol is not soluble in blood and therefore needs to be directed to its destination. High-density cholesterol is usually abbreviated as HDL and this combination of lipoprotein and cholesterol compound is also found throughout the bloodstream. High-density lipoproteins carry unused cholesterol back to the liver for recycling or elimination.Understanding The Cholesterol Level ReadingsToo much LDL is considered a health risk. On the other hand a higher level of HDL is a good thing. This means that more of the cholesterol not needed by the body can be transported back to the liver. Cholesterol readings are given as whole numbers. The number represents the total milligrams of cholesterol in one-tenth of a liter of fluid.A LDL level of 130 or less indicates a normal amount of this type of cholesterol. A level between 130 and 160 is considered moderately high while a level between 160 and 190 usually means trouble. Individuals with an LDL level above 190 are a candidate for severe cardiovascular problems.An HDL level of 60 or above is considered healthy, but a lower reading may indicate a risk of Heart disease. The total cholesterol reading for a healthy person should read no higher than 200. This includes the levels of both the HDL and LDL as well as other lipids present in the blood.