Understanding Heart Health: The Cardiovascular Biomarkers That Matter Most

Heart disease is still the leading cause of death in the US, and standard cholesterol testing hasn’t changed much in decades. The WHOOP Heart Health Panel looks at 81 biomarkers that cover specialized cardiovascular markers like particle burden, vascular inflammation, and fatty acid balance, plus the foundational health markers that put them in context. Dial deeper into what’s actually driving your cardiovascular risk.

Your cholesterol panel checks a small handful of numbers. Total cholesterol, LDL, HDL, triglycerides, and a couple of ratios. If they fall within range, the visit ends the same way: you’re good.

That panel was designed in the 1970s to screen large populations for obvious lipid disorders. It does that well. What it doesn’t do is reflect the underlying processes that drive plaque development, or how your LDL particles are distributed across higher and lower risk profiles.

Forty-two percent of adults with no known heart disease already have atherosclerotic plaque building in their arteries — many with lipid panels that look normal. Traditional lipid testing can appear reassuring even when underlying cardiovascular risk is already present.

Cardiovascular risk assessment has moved past those four markers. Newer tests measure particle count, arterial inflammation, markers linked to endothelial function, fatty acid balance, and kidney-heart interactions: markers that are now available through targeted blood panels.

What are lipids and why do they matter?

Lipids are fats and fat-like substances in your blood, including cholesterol and triglycerides, that play essential roles in cell structure, hormone production, and energy storage. They matter because the types and amounts of lipid-carrying particles in your bloodstream are among the strongest predictors of cardiovascular disease. A standard lipid panel measures four of them:

• Total cholesterol: the sum of all cholesterol in your blood
• LDL cholesterol (LDL-C): estimated cholesterol carried by LDL particles
• HDL cholesterol (HDL-C): cholesterol carried by HDL particles
• Triglycerides: fat molecules in your blood, often tied to diet and metabolic health

Four markers, once a year, compared against population-level reference ranges.

These numbers have real clinical value. Elevated LDL-C correlates with cardiovascular disease. Low HDL-C is associated with higher risk. High triglycerides signal metabolic issues. If your lipid panel is abnormal, your doctor should act on it.

The problem is when it looks normal. LDL-C is an estimate of cholesterol mass carried by LDL particles. But mass and particle count are different things. Two people can have identical LDL-C and very different numbers of actual LDL particles in their blood. The person with more particles has significantly higher risk, even though their cholesterol number looks the same.

A standard lipid panel doesn’t measure particle count or particle size. Lipoprotein(a), a genetically driven risk factor that affects roughly 20% of the population, isn’t on it. Neither are markers of vascular inflammation, omega fatty acid status, endothelial function, or kidney-heart overlap.

Clinical guidelines and expert consensus statements increasingly recognize markers like ApoB and Lp(a) as important additions to traditional lipid testing in certain populations. The 2026 ACC/AHA Dyslipidemia Guideline endorses both for cardiovascular risk assessment.

Deeper cardiovascular testing starts here, with the markers that standard lipid panels leave out.

The cardiovascular biomarkers standard panels miss

ApoB: the particle that matters

Apolipoprotein B (ApoB) is a protein carried by every cholesterol particle that contributes to plaque buildup, one molecule per particle. Measuring ApoB gives you a direct count of how many of those particles are circulating in your blood.

LDL-C estimates the cholesterol inside those particles. ApoB counts the particles themselves. When those two numbers disagree, the risk follows ApoB.

ApoB outperformed LDL-C as a predictor of cardiovascular events in 9 of 9 major head-to-head studies, particularly when the two markers were discordant. In the UK Biobank analysis, every standard deviation increase in ApoB was associated with a 24.4% increase in coronary risk, compared to 20.1% for LDL-C. And 18% of people have discordant ApoB and LDL-C results, where one looks fine and the other doesn’t. In those cases, outcomes track with ApoB.

The 2026 ACC/AHA guideline now endorses ApoB for risk assessment, and the National Lipid Association recommends reclassifying it from experimental to routine testing.

Based on aggregated, de-identified data from approximately 16,000 Advanced Labs members, approximately 38% showed sub-Optimal ApoB by WHOOP functional ranges. For many, a standard lipid panel would have returned normal results.

Lp(a): the genetic risk factor almost nobody checks

Lipoprotein(a), or Lp(a), is an LDL-like particle with an additional protein that makes it bind more readily to artery walls and promote inflammation and clot formation. Your Lp(a) level is largely determined by your genetics. Diet and exercise barely move it.

About 20% of the global population has elevated Lp(a), yet testing rates remain persistently low despite growing guideline support. Multiple international cardiology societies now recommend Lp(a) testing. The 2026 ACC/AHA guideline recommends measuring it at least once in every adult’s lifetime. Because Lp(a) levels are largely genetically determined and remain relatively stable over time, a single test can offer long-term insight into inherited cardiovascular risk.

Elevated Lp(a) increases cardiovascular risk even when LDL-C is well controlled. You can do everything right on paper and still carry significant risk you don’t know about. In fact, it is believed to be the cause of up to 20% of heart attacks, especially those affecting otherwise healthy people. 

Based on aggregated, de-identified data from approximately 16,000 Advanced Labs members, approximately 30% showed sub-Optimal Lp(a) by WHOOP functional ranges.

LDL particle number and size: why two identical cholesterol numbers can mean different things

LDL-C tells you the total cholesterol carried by your LDL particles. LDL particle number (LDL-P) tells you how many of those particles you actually have. The distinction matters because small, dense LDL particles carry less cholesterol each, meaning you can have a “normal” LDL-C while having a high particle count.

In the EPIC-Norfolk Prospective Population Study, LDL particle number predicted coronary artery disease more accurately than LDL cholesterol mass. And the type of particle matters: in the Copenhagen General Population Study of over 38,000 individuals, higher concentrations of small dense LDL cholesterol were associated with higher risk of myocardial infarction and atherosclerotic cardiovascular disease.

Small dense LDL particles spend more time in the bloodstream, are more susceptible to oxidation, and penetrate artery walls more easily than their larger counterparts.

A standard lipid panel gives you one LDL number. The Heart Health Panel breaks that number into particle count, size distribution, and pattern classification, showing what your LDL is actually doing.

What’s happening in your artery walls

Cholesterol in your bloodstream matters. But what matters more is whether that cholesterol is actively interacting with your artery walls and driving inflammation.

MPO: arterial inflammation and oxidative stress

Myeloperoxidase (MPO) is an enzyme released by white blood cells that fuels the oxidative and inflammatory activity associated with plaque buildup and rupture risk.

In a 2003 New England Journal of Medicine study, patients in the top MPO quartile were more than four times as likely to have a myocardial infarction within 30 days. MPO predicted cardiac events even when troponin (the standard heart attack biomarker) was negative.

MPO captures a layer of cardiovascular risk tied to inflammation and oxidative stress: something a standard lipid panel doesn’t reflect.

Lp-PLA2: vascular-specific inflammation

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme linked to inflammatory activity within arterial plaques, particularly those associated with higher cardiovascular risk. Unlike CRP, which rises with any type of inflammation (a sore throat, a sprained ankle, arthritis), Lp-PLA2 is more specific to vascular inflammation.

It’s the only FDA-cleared biomarker for assessing cardiovascular risk through vascular inflammation, and it independently predicts incident coronary heart disease in apparently healthy adults. In the ARIC study of over 12,000 healthy middle-aged adults, those in the highest Lp-PLA2 tertile had a 2.53-fold increased risk of coronary events.

ADMA and SDMA: endothelial dysfunction

Asymmetric dimethylarginine (ADMA) inhibits nitric oxide production. Nitric oxide is the molecule that keeps your arteries flexible, dilated, and resilient to plaque. Elevated ADMA is associated with impaired endothelial function — the earliest detectable change in the life history of an atherosclerotic lesion, before plaque even begins to form.

In a prospective Finnish study published in The Lancet, non-smoking men in the highest ADMA quartile had a 3.9-fold increased risk of acute coronary events. In the AtheroGene Study of 1,874 patients with coronary artery disease, those in the highest third for ADMA had a 2.48-fold higher risk of cardiovascular events and death. SDMA, its symmetric counterpart, provides additional context on vascular health.

These markers can detect cardiovascular risk at its origin, often years before cholesterol levels look concerning on a standard panel.

The Heart Health Panel measures all four of these markers alongside your lipid profile, connecting particle burden to the inflammatory activity happening in your artery walls.

Omega fatty acids and inflammation resolution

Your body’s ability to resolve inflammation depends in part on your fatty acid balance. Omega-3 fatty acids (EPA, DPA, DHA) support the resolution of inflammation, while omega-6 fatty acids (particularly arachidonic acid) promote the inflammatory response. The balance between them matters for long-term cardiovascular health.

A full omega fatty acid profile goes beyond any single marker. EPA, DPA, and DHA serve different biological functions. The Omega-6 to Omega-3 ratio shows whether your system is structurally biased toward inflammation or resolution. Individual variability in fatty acid metabolism is large — some people respond well to dietary changes; others don’t. A blood test is the only way to know where you stand.

Omega status is one of the most actionable cardiovascular biomarkers. Evidence-based target ranges exist, dietary intervention works for most people, and retesting confirms whether your approach is having the intended effect. The Heart Health Panel includes a full nine-marker omega fatty acid profile alongside your lipid and inflammation markers.

The kidney-heart overlap

Kidney function and cardiovascular risk are closely linked. The kidneys regulate blood pressure, fluid balance, and the clearance of metabolic waste. When kidney function declines, even mildly, cardiovascular risk rises.

Cystatin C: a more accurate measure of kidney function

The standard kidney marker is creatinine. A limitation of creatinine is that it’s heavily influenced by muscle mass. If you’re fit and muscular, your creatinine will be higher than average. If you’re older or have less muscle mass, it may look normal even when kidney function is declining.

Cystatin C is less affected by muscle mass, diet, and age the way creatinine is. In the BiomarCaRE project (a multi-cohort European study), Cystatin C-defined chronic kidney disease carried a hazard ratio of 2.14 for cardiovascular mortality, compared to 1.72 for creatinine-based definitions. Cystatin C also detected elevated risk in patients whose creatinine-based kidney function looked normal.

For people who exercise regularly and carry more muscle mass than the average patient, standard creatinine can overestimate kidney function. Cystatin C corrects for that.

Uric acid: metabolic-cardiovascular bridge

Uric acid sits at the intersection of metabolic and cardiovascular health. Elevated levels are associated with hypertension, metabolic syndrome, and increased diabetes risk, each of which feeds back into cardiovascular risk. When interpreted alongside particle burden and oxidative markers like MPO, uric acid helps distinguish temporary lifestyle effects (dehydration, high-purine diet) from sustained metabolic patterns. The Heart Health Panel pairs both kidney markers with the full cardiovascular picture, capturing this connection in one test.

What the WHOOP Heart Health Panel includes

The WHOOP Heart Health Panel tests 81 biomarkers — 21 of which aren’t part of a standard annual blood draw. It covers the cardiovascular system across five domains:

• Particle burden and quality: LDL Particle Number, LDL Small, LDL Medium, LDL Peak Size, LDL Pattern, HDL Large, alongside foundational lipids including ApoB, Lp(a), LDL-C, HDL-C, and triglycerides
• Active plaque biology: MPO, Lp-PLA2
• Endothelial function: ADMA, SDMA
• Resolution capacity: EPA, DPA, DHA, Omega-3 Total, Omega-6 Total, Omega-6/Omega-3 ratio, Arachidonic Acid, Linoleic Acid, AA/EPA ratio
• Cardio-renal modifiers: Cystatin C, Cystatin C eGFR, Uric Acid

The panel also includes the cardiovascular foundation you’d expect from a comprehensive blood draw: hsCRP, homocysteine, standard lipid panel, CBC with differential, full metabolic panel, and iron studies, so you get the baseline covered and the depth added in one test.

Every result is reviewed by a licensed clinician. The panel’s biomarker selection was developed with WHOOP’s Medical Advisory Board, and all testing is exclusively powered by Quest® Diagnostics. $299. No subscription required. No baseline test required. FSA/HSA eligible. Schedule a test at 2,000+ Quest® locations nationwide, right in the WHOOP app.

Frequently asked questions

What’s the difference between LDL cholesterol and ApoB? LDL cholesterol (LDL-C) measures the total cholesterol carried by LDL particles. ApoB counts the actual particles. Two people can have the same LDL-C but very different particle counts — and cardiovascular risk tracks more closely with particle count, not cholesterol mass. ApoB outperformed LDL-C as a risk predictor in every major head-to-head study, and the 2026 ACC/AHA guideline now endorses it for risk assessment.

What do omega fatty acid markers tell you about cardiovascular health? The omega fatty acid profile measures EPA, DHA, and other fatty acids that reflect your omega-3 and omega-6 status. Omega-3 fatty acids support the resolution of inflammation, while omega-6 fatty acids promote the inflammatory response. The balance between them (captured in the Omega-6/Omega-3 ratio and AA/EPA ratio) shows whether your system is structurally biased toward inflammation or resolution. Omega status is one of the most actionable cardiovascular biomarkers because evidence-based target ranges exist and dietary changes can move the numbers.

Why is Lp(a) important if I can’t change it with diet or exercise? Lp(a) is largely genetically determined, and elevated levels increase cardiovascular risk even when LDL-C is well controlled. Knowing your Lp(a) changes clinical decision-making: it affects statin candidacy, risk stratification, and monitoring frequency. The ACC/AHA now recommends measuring it at least once in every adult’s lifetime. About 20% of the population has elevated Lp(a), yet testing rates remain persistently low.

What is Cystatin C and why is it in a heart health panel? Cystatin C measures kidney filtration more accurately than creatinine, especially in people with above-average muscle mass. Kidney function and cardiovascular risk are closely linked: when filtration declines, even mildly, cardiovascular risk rises. Cystatin C detects this earlier and without the muscle-mass bias that makes creatinine less reliable for active people.

Want to understand what standard bloodwork misses across all five health domains? Read: What Your Doctor’s Bloodwork Misses.

WHOOP Advanced Labs includes Specialized Panels, the Comprehensive Health Panel for ongoing longitudinal tracking, and free blood work uploads. Choose the path that fits you. Explore Advanced Labs.

This data is not diagnostic and does not identify individuals; individual results vary.