Types

• There are two different types of cholesterol: low-density lipoprotein, or LDL, and high-density lipoprotein, or HDL. LDL is known as the "bad" cholesterol, while HDL is known as the "good" cholesterol variant because it guards against heart disease.
  
  

Significance

• If you have an HDL levels lower than 40 mg/dl, you might be at greater risk for heart disease.
  
  

Considerations

• An HDL level of 60 mg/dL or higher provides your body with some form of protection against cardiovascular disease.
  
  

Causes

• Low HDL levels can be caused by a variety of factors, the most common of which include obesity, a sedentary lifestyle and smoking.
  
  

Average HDL Range

• According to the American Heart Association, the average man has HDL levels of 40 to 50 mg/dL; the average woman has a range of 50 to 60 mg/dL.