Cholesterol comes in two forms-- HDL and LDL. Your LDL cholesterol is often called "bad cholesterol," and high levels are associated with poor cardiovascular health. Your HDL is generally called "good cholesterol," and high levels improve cardiovascular health. In general, the more you exercise and the better you eat, the higher your HDL.
Cholesterol
Actually, cholesterol is just cholesterol, but LDL and HDL represent two modes of transportation through the blood. LDL stands for low-density lipoprotein, and is a transporter that carries cholesterol from the liver to the body cells. HDL stands for high-density lipoprotein, and it's a transporter that carries cholesterol from the body cells to the liver for excretion. The American Heart Association recommends that LDL be as low as possible, and HDL be as high as possible.
Reason You Need HDL
HDL is your cholesterol disposal mechanism -- it helps you get rid of LDL. You make LDL when you consume fatty foods -- specifically, foods that contain saturated, or animal, fat. LDL then circulates in your bloodstream, and cells can take up the cholesterol from there. Cells need a certain amount of cholesterol, explains Drs. Reginald Garrett and Charles Grisham in their book "Biochemistry," but they won't take up more than they need. If your LDL is high, it's an indication that you have more cholesterol than your cells need, and it stays in the bloodstream, where it clogs arteries and negatively affects heart health.
Where HDL Comes From
HDL is the way your cells package extra cholesterol for excretion. As such, if you have high HDL, it's an indication that your cells are getting rid of excess cholesterol, which helps keep cholesterol out of the bloodstream. Some foods make it easier to produce HDL, while others make it harder. Specifically, saturated and trans fats, or processed fats, decrease your ability to produce HDL. Avoiding these foods helps you produce more HDL.
Exercise and High HDL
One of the best ways to encourage your cells to produce HDL is to exercise regularly, says a 2001 study published in "Arteriosclerosis, Thrombosis, and Vascular Biology." Individuals who exercised for at least 30 minutes three or more times a week had significantly higher HDL levels than those who were more sedentary. If you're exercising regularly, it's to be expected that your HDL levels will be higher than when you're not.
Other High HDL Factors
One more factor that affects your HDL level is moderate alcohol consumption. It appears that moderate consumption of alcoholic beverages -- defined as one drink per day for women or one to two drinks per day for men -- increases your HDL production. In a 2000 study published in the journal "Circulation," researchers determined that alcohol affected the mechanism of HDL production, making it easier for cells to produce HDL. As such, moderate alcohol can be part of a heart-healthy diet.
References
- American Heart Association: What Your Cholesterol Levels Mean
- "Biochemistry"; Reginald Garrett, Ph.D. and Charles Grisham, Ph.D.; 2007
- "Arteriosclerosis, Thrombosis and Vascular Biology"; Effects of Endurance Exercise Training on Plasma HDL Cholesterol Levels Depend on Levels of Triglycerides: Evidence From Men of the Health, Risk Factors, Exercise Training and Genetics; C. Couillard et al; July 2001
- "Circulation"; Alcohol Consumption Raises HDL Cholesterol Levels by Increasing the Transport Rate of Apolipoproteins A-I and A-II; E. De Oliviera e Silva et al; 2000
