High levels of high-density lipoprotein, known as HDL or "good," cholesterol are optimal and protective against disease. Ideally, individuals should aim for 60 mg/dL and above. Both modifiable and unmodifiable factors contribute to an individual's ability to reach or sustain the recommended HDL levels. As stated in a study by the American Heart Association, HDL levels are at least 50 percent genetically determined. While achieving high levels of HDL may be challenging, the reward is living a healthier, disease-free lifestyle.
Function
Cholesterol is a waxy, fat-like substance that is essential to the overall function of the human body. The body can produce cholesterol in the liver or absorb it from the diet. Cholesterol is used to build cell membranes and produce sex hormones, and is crucial for forming bile acids for fat digestion. Moreover, cholesterol combined with protein from the liver is transported throughout the body via lipoproteins, which play a critical role in the complex transport system that exchanges lipids throughout the body.
Protection Against Heart Disease
HDL is the smallest,of the four main classes of lipoproteins. HDL molecules are suspended in the plasma and protect the body by picking up excess cholesterol from the arterial walls and delivering it to the liver, where it is metabolized. While several risk factors for heart disease, including genetics, gender, age and race cannot be changed, elevating HDL levels and lowering low-density lipoprotein or LDL levels through diet and exercise can substantially lower one's risk for heart disease. According to the American Heart Association, the risk of coronary heart disease is lower for those with higher concentrations of HDL, especially levels exceeding 60 mg/dL.
Protection Against Stroke
According to the National Stroke Association, stroke is the third leading cause of death in the United States and a leading cause of adult diasbility. HDL levels are inversely related to incidence of stroke. Low levels of HDL and high levels of LDL significantly increase risk for stroke. Potential explanations for why HDL prevents strokes include reduced blockage. A study by the American Heart Association found that among the groups studied, people with high levels of HDL cholesterol had a lower risk of ischemic stroke by 50 percent.
Exercise to Increase Your HDL
The American Heart Association's Scientific Position indicates that endurance exercise training is the most effective way to increase HDL levels. Regular exercise stimulates lipoprotein lipase activity in skeletal muscle and adipose tissue, which stimulates the clearance of triglycerides from the blood. This response appears to relate to the intensity, frequency and duration of individual sessions and the overall training period. Therefore, consistent, rigorous exercise over a period of time produces the greatest increases in HDL.
Other Ways to Boost HDL
In addition to aerobic exercise, choosing monounsaturated fats over saturated fats and limiting alcohol intake are other ways to successfully boost HDL while loweing LDL levels.
According to a study published in the American Journal of Clinical Research, daily consumption of 750 mL of orange juice increased HDL levels by 21 percent. These findings are attributable to the high content of vitamin C, folate and flavonoids contained in orange juice.
As reported by the Mayo Clinic, niacin has the highest potential of all drugs to increase HDL and has been shown to increase levels by 15 to 25 percent. However, because niacin is usually given at high doses in order to increase HDL, individuals considering niacin as a treatment should first consult with their physician about potential side effects.
References
- "Advanced Fitness Assessment and Exercise Prescription"; Vivian H. Heyward, PhD.; 2006
- Mayo Clinic: Cholesterol levels: What numbers should you aim for?
- American Heart Association: Genetics of Increased HDL Cholesterol Levels
- American Heart Association: HDL-Cholesterol, Total Cholesterol, and the Risk of Stroke in Middle-Aged British Men
- American Journal of Clinical Nutrition: HDL-Cholesterol-Raising Effect of Orange Juice in Subjects with Hypercholesterolemia
