Coronary calcium score: How old are your arteries?

Imagine being able to take a snapshot of your coronary arteries and see whether calcified plaque has built up in their walls. This is what the coronary artery calcium score (CAC score) does: a fast, non-contrast CT test that can meaningfully refine how you and your clinician understand cardiovascular risk.

A 2023 JAMA analysis found that CAC improved coronary heart disease risk discrimination when added to traditional risk factors, while a 2023 CONFIRM registry analysis found that people with CAC >300 and no prior ASCVD had event rates comparable to people with established ASCVD.

That does not mean everyone needs the scan. CAC is most useful when preventive-treatment decisions are uncertain and the result would change management.

What you will learn:

What the coronary calcium score is and how the exam works
How to interpret your results and what they mean for your health
The link between arterial calcification, biological age, and mortality
7 scientifically validated strategies to reduce your risk
Who should get tested and when

Quick answer

A CAC score is best understood as an arterial-age test for calcified coronary plaque. A score of 0 usually means low near-term risk, but it is not a guarantee; higher scores identify people who usually need more intensive lipid, blood pressure, glucose, and lifestyle management.

The most important numbers are the absolute Agatston score and the age/sex/race percentile. In the 2026 ACC/AHA dyslipidemia guideline, CAC now directly informs statin intensity and LDL-C goals in adults with subclinical coronary atherosclerosis.

Key facts

CAC score -> calcified plaque burden: the Agatston score quantifies calcium in coronary arteries on a non-contrast CT scan.
CAC = 0 -> low risk, not no risk: soft plaque can still exist, and rescreening depends on diabetes, smoking, family history, and baseline risk.
CAC 1-99 -> early atherosclerosis: 2026 guidance supports moderate-intensity statin therapy when CAC is present and below the 75th percentile.
CAC 100-299 or >=75th percentile -> higher risk: 2026 guidance supports stronger LDL-C lowering toward <70 mg/dL.
CAC 300-999 -> severe subclinical atherosclerosis: 2026 guidance recommends LDL-C lowering by >=50% toward <70 mg/dL; intensification toward <55 mg/dL is reasonable in selected patients.
CAC >=1000 -> very high risk phenotype: 2026 guidance supports high-intensity statin plus additional lipid-lowering therapy toward LDL-C <55 mg/dL.

Related guides: ApoB, Lp(a), blood pressure targets.

What is the coronary calcium score?

The coronary calcium score — also known as the Agatston score, named after the cardiologist who developed it in 1990 — is a measurement of the amount of calcium deposited in the coronary arteries. It is obtained through a non-contrast cardiac CT scan: a fast, non-invasive procedure with a low radiation dose.

Quick definition: The coronary artery calcium score (CAC score) is a non-contrast CT measurement of calcified plaque in the heart arteries. It refines cardiovascular risk, but it does not detect soft plaque or replace a clinician-led prevention plan.

Why calcium builds up in arteries

Coronary calcification does not happen by chance. It is the end result of a process called atherosclerosis — the buildup of plaque in arterial walls that begins silently decades before any symptoms appear.

Here is how it progresses:

Endothelial damage: factors such as hypertension, smoking, high blood sugar, and chronic inflammation damage the inner lining of the arteries
Lipid infiltration: LDL particles (especially small, dense ones, measurable via ApoB) penetrate the damaged arterial wall
Inflammatory response: the immune system reacts; macrophages engulf oxidized fat, forming “foam cells”
Plaque formation: a lipid core surrounded by a fibrous cap develops
Calcification: over time, calcium deposits in the plaques — and this is the stage the CAC score detects

Calcium in your arteries is like scar tissue: it tells the story of years of silent vascular damage.

How the exam works

The procedure

The exam is surprisingly straightforward:

Duration: 5–10 minutes
Preparation: none required (no fasting, no contrast dye)
Procedure: you lie in the CT scanner, hold your breath for a few seconds, and the scanner captures ECG-gated images of the heart
Radiation: very low dose, approximately 1 mSv (equivalent to a few months of background natural radiation)
Cost: typically between $100 and $400 in the US, often not covered by insurance when used as a screening tool

How the score is calculated

The software analyzes each calcium deposit in the coronary arteries and assigns a score based on:

Area of the calcified deposit (in mm²)
Density of the calcium (measured in Hounsfield units)

The individual scores are summed to produce the total Agatston score. Beyond the absolute score, a percentile adjusted for age, sex, and ethnicity is also calculated — a figure that is often more informative than the raw number.

How to interpret your results

Standard CAC score classification

Score	Category	What it usually means
0	No calcified plaque detected	Low near-term risk, but not zero risk
1-10	Minimal calcification	Early atherosclerosis is present
11-99	Mild calcification	Risk is higher than CAC 0 and depends strongly on percentile
100-299	Moderate calcification	Coronary artery disease is present; prevention usually intensifies
300-999	Severe calcification	High-risk subclinical atherosclerosis
>=1,000	Very high CAC burden	A distinct very-high-risk phenotype in recent CAC guidance

The power and limits of a zero score

A CAC score of 0 is powerful because it identifies many people with very low short-term event risk. In the 2018 ACC/AHA cholesterol guideline, and retained in later guidance, CAC = 0 can support deferring or delaying statin therapy in selected intermediate-risk adults when diabetes, current smoking, and a strong family history of premature coronary disease are absent.

But a zero score does not mean perfect arteries. CAC detects calcified plaque, not non-calcified “soft” plaque. Events can still occur, especially in smokers, people with diabetes, strong family history, very high LDL-C, or high Lp(a).

The rescan interval is not one fixed number. A MESA analysis estimated conversion from CAC 0 to CAC >0 often occurs over about 3-7 years depending on demographics and risk profile. Older long-term cohort work showed that CAC 0 can remain reassuring for up to 15 years in selected low-risk asymptomatic people. In practice, many guidelines use a 5-10 year repeat window for low-risk CAC 0, and shorter intervals when risk factors are present.

Percentile matters

The absolute score is only half the story. A CAC of 50 in a 75-year-old has a different meaning than CAC 50 in a 40-year-old. Percentile compares your score with people of the same age, sex, and race or ethnicity.

Below the 75th percentile: interpret mainly by absolute CAC category and risk factors.
At or above the 75th percentile: risk is higher than expected for age and sex, and prevention usually becomes more aggressive.
Very young adults with any CAC: even small scores can be meaningful because calcification is uncommon at younger ages.

Coronary calcium and aging: what the research says

CAC as a clock of arterial aging

Your arteries have a risk profile of their own, which may differ greatly from your chronological age. CAC can be translated into a communication tool sometimes called “coronary age,” but it is still a risk model based on calcified plaque and traditional risk factors, not a literal clock of the whole vascular system. For an earlier window into vascular aging — before calcification develops — carotid intima-media thickness measures the actual structural thickening of arterial walls and is particularly useful in adults under 50.

A study from the Intermountain Heart Collaborative Study showed that the CAC score predicts not only heart attack risk, but also all-cause mortality — suggesting that coronary calcification reflects a process of systemic aging, not just cardiac aging.

Calcification and biological age

Research has revealed deep connections between CAC and markers of biological aging:

Chronic inflammation: elevated levels of C-reactive protein (CRP) and IL-6 are associated with faster progression of calcification
Oxidative stress: oxidative damage to LDL accelerates plaque formation and calcification
Cellular senescence: senescent vascular smooth muscle cells actively promote calcium deposition
Endothelial dysfunction: deterioration of the arterial lining is both a cause and a consequence of calcification
Elevated homocysteine: homocysteine damages the endothelium and promotes atherogenesis through impaired methylation — a frequently overlooked driver of CAC progression, especially in individuals with MTHFR genetic variants

In other words, a high CAC score is not just a cardiology number. It is a signal of cumulative vascular injury and higher cardiovascular risk that should be interpreted with the whole clinical picture.

Women vs. men: important differences

Coronary calcification follows different patterns between sexes:

Women develop calcification on average 10–15 years later than men, thanks to the protective effect of estrogen
After menopause, the rate of progression in women accelerates significantly
At the same CAC score, women tend to carry a higher relative risk than men — a score of 100 in a 55-year-old woman is more concerning than the same score in a man of the same age
The percentile is especially important in women to properly contextualize results

7 strategies to protect your arteries from calcification

1. Lower ApoB-containing particles

ApoB-containing particles drive plaque formation. In the 2026 ACC/AHA dyslipidemia guideline, CAC now helps set LDL-C goals in primary prevention:

CAC 1-99 and below the 75th percentile: moderate-intensity statin therapy is reasonable, with LDL-C goal <100 mg/dL.
CAC 100-299 or at/above the 75th percentile: stronger LDL-C lowering toward <70 mg/dL is reasonable.
CAC 300-999: lipid-lowering therapy, usually with statin therapy as first line, is recommended to lower LDL-C by at least 50% and reach LDL-C <70 mg/dL; intensifying toward <55 mg/dL can be reasonable when risk remains high.
CAC >=1,000: high-intensity statin plus additional lipid-lowering therapy is reasonable to reach LDL-C <55 mg/dL.

Discuss ApoB, non-HDL-C, LDL-C, and Lp(a) with your clinician. CAC helps determine intensity; it does not replace clinical judgment.

2. Control blood pressure

High blood pressure accelerates endothelial injury and plaque progression. Home blood-pressure monitoring, sodium reduction, adequate potassium intake, weight management, sleep apnea treatment, and medication when needed are central.

3. Improve glucose and insulin resistance

Diabetes and insulin resistance accelerate calcification and events. Track HbA1c, fasting glucose, waist circumference, and, when useful, fasting insulin or continuous glucose patterns.

4. Exercise consistently

Regular aerobic and resistance training improve endothelial function, blood pressure, insulin sensitivity, and inflammation. Exercise can coexist with higher CAC in long-term endurance athletes, often with denser plaque; the risk interpretation still depends on the whole clinical picture.

5. Use a Mediterranean-style dietary pattern

Prioritize unsaturated fats, legumes, whole grains, vegetables, fruit, nuts, fish, and minimally processed foods. Vitamin K2, omega-3s, and other nutrients may be useful in selected people, but they should not distract from LDL-C, ApoB, blood pressure, glucose, and smoking.

6. Stop smoking and reduce pollution exposure

Smoking is one of the strongest accelerators of atherosclerosis. Quitting, avoiding secondhand smoke, and reducing PM2.5 exposure in polluted areas lower vascular risk.

7. Treat sleep and stress as cardiovascular inputs

Poor sleep, sleep apnea, chronic stress, and low recovery increase blood pressure, glucose variability, inflammation, and sympathetic tone. Track sleep, HRV, and resting heart rate as supporting data, not as replacements for medical risk management.

Who should get tested and when

Current guideline role

CAC scoring is most useful when the decision about preventive medication is uncertain. The 2026 ACC/AHA dyslipidemia guideline expands CAC use by explicitly linking CAC categories to lipid-lowering intensity and by recognizing incidental CAC on non-gated chest CT scans as clinically meaningful.

The test is most often considered for:

Adults in the borderline or intermediate primary-prevention risk range when statin decisions are uncertain.
Men age 40 or older and women age 45 or older when subclinical coronary atherosclerosis would change treatment.
People with family history of premature coronary artery disease, elevated Lp(a), ApoB elevation, metabolic risk, or other risk enhancers.
Patients with incidental coronary calcium seen on chest CT, where formal reporting can trigger risk discussion without another scan.

When it is usually not helpful

CAC is usually not needed when someone is already known to have ASCVD or already clearly needs aggressive lipid-lowering therapy. It is also not a universal screening test for very low-risk young adults.

How often to repeat it

For CAC = 0, many clinicians consider repeat scanning in about 5-10 years, sooner when risk factors are strong. For CAC 1-99, repeat testing after about 3-5 years may be considered if it would change management. For CAC >100, the first scan often provides most of the actionable information; treatment intensity matters more than repeatedly chasing the score.

Do not repeat CAC just to see if calcium goes down. Statins can increase plaque density and CAC while lowering event risk.

How SuperAge helps you monitor cardiovascular health

Tracking cardiovascular health goes beyond a single exam. It requires continuous monitoring of parameters that — taken together — provide a complete picture of arterial aging.

Integration with key biomarkers

SuperAge lets you track the biomarkers most closely correlated with cardiovascular health and arterial calcification:

LDL cholesterol and ApoB: monitor your cumulative exposure to atherogenic risk over time
Glucose and HbA1c: keep metabolic risk in check
CRP and inflammatory markers: inflammation is the engine of atherosclerosis

Monitoring through Apple Watch

The data you collect daily from your wrist is more relevant than you might think:

HRV (heart rate variability): an indicator of chronic stress and autonomic nervous system health — both linked to atherosclerosis progression
Resting heart rate: elevated values are associated with greater inflammation and cardiovascular risk
Physical activity: SuperAge tracks your exercise minutes and helps you hit the targets that protect your arteries

Biological age as the big picture

The CAC score is a snapshot of your coronary arteries at a specific moment in time. The biological age calculated by SuperAge integrates blood biomarkers and wearable data to give you a dynamic, continuous view of your aging process — including vascular aging.

Frequently asked questions

Can the CAC score decrease over time?

Usually no. The goal is to slow progression and reduce events, not to make calcium disappear. Statins can increase calcium density while stabilizing plaque and lowering risk.

Is the test dangerous?

For appropriate candidates, the radiation dose is low, often around 1 mSv, and the scan does not require contrast dye. The benefit depends on whether the result would change management.

Can I have a heart attack with a CAC score of 0?

Yes. CAC 0 greatly lowers near-term probability, but it does not rule out soft plaque, spasm, clotting, smoking-related risk, diabetes risk, or genetically driven risk such as high Lp(a).

Do I need statins if my CAC score is high?

Often, but the decision should be made with your clinician. In current guidelines, CAC >0 generally strengthens the case for lipid-lowering therapy, and CAC >=100 or high percentile strengthens it further.

Should I get a coronary CT angiogram instead?

Not usually for routine screening. CAC scoring estimates calcified plaque burden with low radiation and no contrast. CT angiography shows soft plaque and stenosis but uses contrast and is usually reserved for symptoms or specific clinical questions.

Key takeaways

CAC measures calcified coronary plaque: it is one of the best tools for refining cardiovascular risk beyond traditional factors.
CAC 0 is reassuring, not absolute: soft plaque and high-risk clinical contexts still matter.
Percentile changes interpretation: a small score in a young person can be more concerning than the same score in an older person.
2026 guidance is more CAC-stratified: CAC 1-99, 100-299, 300-999, and >=1,000 now map to different lipid-lowering intensity discussions.
The score does not need to fall to reduce risk: stabilizing plaque and lowering events matters more than lowering the Agatston number.

Start protecting your arteries today

Your coronary arteries tell the story of your lifestyle over the past 20 years. The good news is that you can still change the next 20. Every choice you make today — from the food you eat to how you move to how you manage stress — influences the speed at which your arteries age.

Ready to take control? Download SuperAge and start tracking the key biomarkers of cardiovascular health alongside your biological age.

References

ACC/AHA et al. - “2026 Guideline on the Management of Dyslipidemia” - Circulation (2026) - DOI
American College of Cardiology - “ACC/AHA Issue Updated Guideline for Managing Lipids, Cholesterol” (2026) - ACC
Cainzos-Achirica M et al. - “Guideline-Directed Application of Coronary Artery Calcium Scores for Primary Prevention of ASCVD” - JACC: Cardiovascular Imaging (2025) - PubMed
Dzaye O et al. - “Warranty Period of a Calcium Score of Zero: Comprehensive Analysis From MESA” - JACC: Cardiovascular Imaging (2021) - DOI
Budoff MJ et al. - “Ten-year association of coronary artery calcium with ASCVD events: MESA” - European Heart Journal (2018) - PubMed
Valenti V et al. - “A 15-Year Warranty Period for Asymptomatic Individuals Without Coronary Artery Calcium” - JACC: Cardiovascular Imaging (2015) - DOI
SPRINT Research Group - “A Randomized Trial of Intensive versus Standard Blood-Pressure Control” - New England Journal of Medicine (2015) - PubMed
Al-Mallah MH et al. - “When Does a Calcium Score Equate to Secondary Prevention? Insights From the CONFIRM Registry” - JACC: Cardiovascular Imaging (2023) - PubMed
Mosley JD et al. - “Coronary Artery Calcium and Polygenic Risk Scores to Predict Coronary Heart Disease Events” - JAMA (2023) - JAMA
Blaha MJ et al. - “Derivation of a Coronary Age Calculator Using Traditional Risk Factors and Coronary Artery Calcium” - Journal of the American Heart Association (2021) - PubMed
SPRINT Research Group - “A Randomized Trial of Intensive versus Standard Blood-Pressure Control” - New England Journal of Medicine (2015) - PubMed

Last updated: 2026-07-08. This article is regularly reviewed for accuracy.