HDL Cholesterol
HDL is the “good” cholesterol — it acts like a vacuum cleaner, removing excess cholesterol FROM arteries and returning it to the liver (reverse cholesterol transport). Higher HDL = lower cardiovascular risk. BUT: the “HDL paradox” — medications that raise HDL haven’t reduced heart attacks; naturally high HDL is protective, artificially raised HDL is not. Exercise, quitting smoking, and weight loss are the best ways to raise HDL naturally.
HDL cholesterol — high-density lipoprotein cholesterol — is famously known as the “good” cholesterol. Unlike LDL which deposits cholesterol in artery walls, HDL particles act like tiny vacuum cleaners, picking up excess cholesterol from arteries and transporting it back to the liver for recycling or disposal. This reverse cholesterol transport is one of the body’s key defenses against atherosclerosis.
Why does this matter? Higher HDL levels have consistently been associated with lower rates of heart attacks and strokes in population studies. People with very low HDL face increased cardiovascular risk even if their LDL is normal. HDL appears to protect arteries through multiple mechanisms beyond just removing cholesterol — including anti-inflammatory and antioxidant effects.
While raising HDL with medications hasn’t proven as beneficial as hoped, naturally high HDL remains a marker of cardiovascular health. Low HDL signals metabolic dysfunction and increased risk — often accompanying the same lifestyle factors that raise LDL.
Key Benefits of Testing
HDL cholesterol testing reveals whether you have adequate levels of this protective lipoprotein. Low HDL is an independent cardiovascular risk factor — meaning it increases your risk even when other lipids are normal.
HDL helps interpret your total cholesterol. A high total cholesterol might be acceptable if it’s driven by high HDL rather than high LDL. Without knowing HDL, you can’t accurately assess risk from total cholesterol alone.
What Does This Test Measure?
HDL cholesterol measures the amount of cholesterol carried in high-density lipoprotein particles. These are the smallest, densest lipoproteins, consisting of about 50% protein and 50% lipid.
How HDL Works
Reverse cholesterol transport: HDL’s primary protective function is removing excess cholesterol from peripheral tissues, including artery walls, and returning it to the liver. This process — reverse cholesterol transport — helps prevent cholesterol accumulation in arteries.
The HDL lifecycle:
- Nascent HDL particles are produced by the liver and intestines
- These particles acquire cholesterol from cells throughout the body
- As they collect cholesterol, HDL particles mature and enlarge
- Mature HDL delivers cholesterol to the liver for excretion in bile
- The cycle continues, constantly removing excess cholesterol
Beyond Cholesterol Removal
HDL provides protection through multiple mechanisms:
Anti-inflammatory effects: HDL reduces inflammation in artery walls, a key driver of atherosclerosis.
Antioxidant properties: HDL prevents oxidation of LDL — oxidized LDL is particularly damaging to arteries.
Endothelial protection: HDL helps maintain healthy blood vessel lining function.
Antithrombotic effects: HDL may reduce blood clot formation.
HDL vs. LDL — The Key Difference
LDL (Low-Density Lipoprotein): Carries cholesterol TO tissues, including artery walls. Deposits cholesterol. Higher levels = more plaque.
HDL (High-Density Lipoprotein): Carries cholesterol AWAY from tissues, back to the liver. Removes cholesterol. Higher levels = less plaque.
Why This Test Matters
Independent Cardiovascular Risk Factor
Low HDL increases cardiovascular risk independent of LDL levels. Even with optimal LDL, very low HDL signals increased risk. HDL is part of standard cardiovascular risk calculations.
Completes the Lipid Picture
Total cholesterol alone is incomplete. Knowing HDL reveals whether high total cholesterol is concerning (from high LDL) or less worrisome (from high HDL). HDL helps calculate non-HDL cholesterol and the total cholesterol/HDL ratio — both predictive of risk.
Identifies Metabolic Dysfunction
Low HDL is a core component of metabolic syndrome, clustering with high triglycerides, central obesity, elevated blood pressure, and impaired glucose. Low HDL often indicates underlying insulin resistance.
Monitors Lifestyle Effects
Exercise, weight loss, smoking cessation, and moderate alcohol all raise HDL. Tracking HDL shows whether lifestyle changes are producing measurable metabolic benefits.
Guides Risk Assessment
HDL levels influence decisions about treatment intensity. Very low HDL may warrant more aggressive LDL lowering or additional cardiovascular risk management.
What Can Affect Your HDL?
Factors That RAISE HDL (Beneficial)
Exercise:
- Regular aerobic exercise is one of the most effective HDL boosters
- Both intensity and duration matter
- Can raise HDL by 5-10% or more
Weight loss:
- Losing excess weight increases HDL
- For every 6-7 pounds lost, HDL may increase by about 1 point
Smoking cessation:
- Quitting smoking significantly raises HDL
- One of many cardiovascular benefits of quitting
Moderate alcohol:
- Modest alcohol consumption is associated with higher HDL
- However, risks often outweigh benefits — not recommended to start drinking for HDL
Healthy fats:
- Replacing saturated fat with unsaturated fat can modestly improve HDL
- Olive oil, nuts, avocados, fatty fish
Genetic factors:
- Some people are genetically blessed with high HDL
- Strong family patterns often exist
Female sex:
- Women typically have higher HDL than men
- Estrogen raises HDL
Factors That LOWER HDL (Concerning)
Smoking:
- One of the most potent HDL suppressors
- Lowers HDL by 10-15%
Obesity:
- Especially central/abdominal obesity
- Associated with metabolic syndrome pattern
Physical inactivity:
- Sedentary lifestyle associated with lower HDL
Poor diet:
- Very high carbohydrate intake (especially refined)
- Trans fats lower HDL
- Very low fat diets may lower HDL
Metabolic conditions:
- Type 2 diabetes and insulin resistance
- Metabolic syndrome
- High triglycerides (often inversely related to HDL)
Medications:
- Beta-blockers (some)
- Anabolic steroids
- Progestins
- Benzodiazepines
Genetic factors:
- Some genetic variants cause low HDL
- Familial hypoalphalipoproteinemia
Testing Considerations
Fasting: HDL is minimally affected by recent meals. Non-fasting measurement is acceptable, though fasting is often done for simultaneous triglyceride measurement.
Acute illness: HDL may temporarily decrease during acute illness or surgery. Test when stable.
Consistency: HDL can vary slightly between tests. Trends over time are more meaningful than single values.
When Should You Get Tested?
As Part of Standard Lipid Panel
HDL is always measured as part of a complete lipid panel:
- Adults: starting at age 20, then every 4-6 years if normal
- More frequently with risk factors or abnormal results
- Men over 45, women over 55: every 1-2 years
With Metabolic Risk Factors
HDL should be checked with:
- Central obesity
- Diabetes or prediabetes
- High triglycerides
- Hypertension
- Metabolic syndrome
Evaluating Family History
Family history of very low HDL or early cardiovascular disease warrants screening.
Monitoring Lifestyle Changes
When making lifestyle changes (exercise, weight loss, quitting smoking), repeat testing shows whether HDL is improving.
On Certain Medications
Some medications affect HDL; monitoring ensures no adverse effects.
Understanding Your Results
HDL interpretation differs from LDL — higher is generally better:
HDL Categories
Low HDL: Associated with increased cardiovascular risk. Often part of metabolic syndrome. Warrants attention to lifestyle factors and overall cardiovascular risk management.
Normal/Acceptable HDL: Adequate for cardiovascular protection when combined with controlled LDL and triglycerides.
High HDL: Historically considered optimal and protective. However, very high HDL (especially from genetic causes or medications) may not provide additional benefit.
Sex Differences
Women typically have higher HDL than men due to estrogen effects. What’s considered low differs by sex — lower thresholds apply to men.
The HDL Paradox
While low HDL is clearly associated with higher risk, very high HDL isn’t always better:
Naturally high HDL: Associated with lower cardiovascular risk in population studies.
Drug-raised HDL: Medications that raise HDL haven’t reduced cardiovascular events as expected. Simply raising HDL numbers isn’t enough — HDL function matters.
Genetically very high HDL: Some genetic variants causing extremely high HDL don’t provide extra protection and may even increase risk in certain cases.
Total Cholesterol/HDL Ratio
This ratio provides additional risk information:
- Lower ratio = better
- Ratio considers both total cholesterol burden and protective HDL
What to Do About Abnormal Results
For Low HDL
Lifestyle modifications (most effective):
- Exercise: Regular aerobic activity is the best HDL booster. Aim for 150+ minutes moderate or 75+ minutes vigorous weekly
- Quit smoking: One of the most impactful changes
- Lose weight: If overweight, weight loss raises HDL
- Reduce refined carbohydrates: Replace with healthy fats and protein
- Choose healthy fats: Olive oil, nuts, fatty fish, avocados
- Consider moderate alcohol: If you drink, moderate consumption may help — but don’t start drinking for this purpose
Address underlying conditions:
- Optimize diabetes control
- Treat metabolic syndrome
- Reduce triglycerides (often raises HDL)
- Review medications that may lower HDL
Medications (limited role):
- No current medications are primarily prescribed to raise HDL
- Niacin raises HDL but hasn’t reduced cardiovascular events in trials
- CETP inhibitors raised HDL but failed to improve outcomes
- Focus remains on LDL lowering and lifestyle
For High HDL
Naturally high HDL is generally favorable and requires no intervention. However:
- Don’t assume high HDL eliminates cardiovascular risk — LDL still matters
- Very high HDL warrants evaluation if unexpected or changing
- Continue healthy lifestyle regardless of HDL level
Related Health Conditions
Metabolic Syndrome
Low HDL Is a Core Component: Metabolic syndrome is defined by the combination of low HDL, high triglycerides, central obesity, elevated blood pressure, and elevated glucose. This cluster dramatically increases cardiovascular risk.
Type 2 Diabetes
Diabetic Dyslipidemia: Diabetes typically causes low HDL with high triglycerides — the “atherogenic dyslipidemia” pattern. This contributes significantly to the cardiovascular risk in diabetes.
Coronary Artery Disease
HDL and Heart Disease: Low HDL is an independent risk factor for coronary disease. It’s part of comprehensive cardiovascular risk assessment and treatment planning.
Obesity
Weight and HDL: Obesity, especially central obesity, is strongly associated with low HDL. Weight loss is one of the most effective ways to raise HDL naturally.
Familial Low HDL
Genetic Conditions: Some inherited conditions cause very low HDL (hypoalphalipoproteinemia). These increase cardiovascular risk and may require specialized management.
Why Regular Testing Matters
HDL is a key component of cardiovascular risk assessment. Regular testing catches declining HDL that often accompanies weight gain, decreased activity, or developing metabolic dysfunction. It also confirms when lifestyle changes are producing measurable improvements.
As part of the standard lipid panel, HDL should be monitored throughout life to maintain optimal cardiovascular health.
Related Biomarkers Often Tested Together
Total Cholesterol — HDL is part of total cholesterol. Knowing both allows ratio calculation.
LDL Cholesterol — The “bad” cholesterol. Primary target of treatment.
Triglycerides — Often inversely related to HDL. High triglycerides with low HDL is the metabolic syndrome pattern.
Non-HDL Cholesterol — Total minus HDL. Captures all atherogenic particles.
Apolipoprotein B — May better predict risk than LDL alone.
Glucose — Low HDL often accompanies insulin resistance and diabetes.
Note: Information provided in this article is for educational purposes and doesn’t replace personalized medical advice.
Frequently Asked Questions
HDL (high-density lipoprotein) cholesterol is the “good” cholesterol. HDL particles remove excess cholesterol from arteries and transport it back to the liver for disposal. This reverse cholesterol transport helps prevent plaque buildup.
While LDL deposits cholesterol in artery walls (causing plaque), HDL removes cholesterol from arteries. Higher HDL levels are associated with lower cardiovascular risk — hence “good” cholesterol.
Higher is generally better. Low HDL increases cardiovascular risk. Target levels differ by sex — women naturally have higher HDL than men. Your provider interprets HDL in context of your full lipid panel and overall risk.
Regular exercise is most effective. Other strategies: quit smoking, lose excess weight, replace refined carbs with healthy fats, and if you drink alcohol, do so moderately. There are no medications currently recommended primarily to raise HDL.
Not necessarily. While low HDL is clearly harmful, very high HDL (especially from genetic causes) may not provide extra benefit. Medications that raise HDL haven’t reduced heart disease as expected — suggesting HDL function matters more than HDL levels alone.
Trials of drugs that raise HDL (niacin, CETP inhibitors) failed to reduce cardiovascular events. The lesson: HDL level is a marker of cardiovascular health, but artificially raising the number doesn’t recreate the benefits of naturally high HDL.
HDL is minimally affected by recent meals, so non-fasting is acceptable. However, lipid panels often include triglycerides, which require fasting for accuracy.
Smoking significantly lowers HDL — typically by 10-15%. Quitting smoking raises HDL substantially and is one of the best things you can do for cardiovascular health.
References
Key Sources:
- Rosenson RS, et al. HDL and atherosclerotic cardiovascular disease: genetic insights into complex biology. Nat Rev Cardiol. 2018;15(1):9-19.
- Grundy SM, et al. 2018 AHA/ACC Guideline on the Management of Blood Cholesterol. Circulation. 2019;139(25):e1082-e1143.
- Voight BF, et al. Plasma HDL cholesterol and risk of myocardial infarction: a mendelian randomisation study. Lancet. 2012;380(9841):572-580.
