Longevity biomarkers test: which ones really matter

Longevity clinics now sell panels with dozens of markers and a "biological age" at the end. Some of those numbers have decades of evidence behind them. Others are interesting research tools that are not ready to guide your choices. Here's how to tell them apart, with the markers ranked by how strong the evidence is.

What makes a good longevity biomarker?

A useful marker should predict future disease or death, be measurable reliably and, ideally, respond to changes you can make, with that change linked to better outcomes. A 2023 framework from the Biomarkers of Aging Consortium (Moqri et al., Cell) stressed that the field still lacks agreed standards for validating ageing biomarkers. That is why the "boring" markers your doctor already uses often beat the fashionable ones.

The markers, ranked by evidence

Marker	What it reflects	Strength of evidence	How to measure
VO2max (cardiorespiratory fitness)	Heart, lungs, blood and muscle working together	Strong, large cohorts	Lab test, field test or watch estimate
Blood pressure	Strain on arteries, heart, brain and kidneys	Strong, including trials	Home or clinic cuff
ApoB (or LDL / non-HDL cholesterol)	Number of artery-clogging lipoprotein particles	Strong, causal for heart disease	Blood test
HbA1c	Average blood sugar over about three months	Strong	Blood test
Grip and leg strength	Muscle function and reserve	Moderate to strong, observational	Dynamometer
Waist-to-height ratio	Central (abdominal) fat	Moderate to strong	Tape measure
Resting heart rate	Fitness and autonomic balance	Moderate, observational	Watch or pulse check
Epigenetic clocks	DNA methylation patterns linked to age	Promising, not clinical	Blood or saliva kit

VO2max

In 122,007 patients who had a treadmill test at Cleveland Clinic (Mandsager et al., 2018), the least fit had about five times the adjusted risk of death of the elite group, and low fitness carried a risk comparable to or greater than smoking or diabetes. Fitness is also trainable, which makes it a marker you can act on. For the full story see VO2max and longevity, and for the newest studies read our 2025–2026 research update. Get an estimate with our VO2max calculator or see your fitness age.

Blood pressure

Blood pressure is one of the few markers where lowering it has been tested in large trials. A meta-analysis of 123 studies with more than 600,000 participants (Ettehad et al., 2016) found that each 10 mmHg reduction in systolic pressure was linked to a 13% reduction in all-cause mortality. Fitness helps too, see VO2max, heart disease and blood pressure.

ApoB

Each LDL, VLDL and related particle carries one ApoB molecule, so ApoB counts the particles that can enter artery walls. A 2019 review in JAMA Cardiology (Sniderman et al.) argued that ApoB unifies and simplifies the information from conventional lipid tests. If ApoB isn't available, LDL and non-HDL cholesterol still give useful information.

HbA1c

In a community cohort of adults without diabetes (Selvin et al., NEJM, 2010), higher HbA1c predicted later diabetes, cardiovascular disease and death. It's cheap, needs no fasting, and fitness strongly affects it (see VO2max, diabetes and insulin sensitivity).

Strength

A meta-analysis of about 1.9 million adults (García-Hermoso et al., 2018) found that higher grip strength was linked to a 31% lower risk of death from any cause, and higher knee extension strength to a 14% lower risk. In the PURE study across 17 countries (Leong et al., 2015), each 5 kg lower grip strength was associated with about 16% higher all-cause mortality. See strength training for runners.

Waist-to-height ratio and resting heart rate

A meta-analysis of studies with more than 300,000 adults (Ashwell et al., 2012) found waist-to-height ratio was better than BMI or waist alone at detecting cardiometabolic risk. For resting heart rate, a meta-analysis of 46 studies (Zhang et al., 2016) linked every 10 beats per minute higher to about 9% higher all-cause mortality. Resting heart rate is easy to track but reacts to sleep, stress and illness (see resting heart rate and HRV).

Biological age clocks: promising, not clinical

Epigenetic clocks, reviewed by Horvath and Raj in Nature Reviews Genetics (2018), estimate age from DNA methylation with striking accuracy, and newer versions predict health outcomes in research cohorts. That's exciting. But:

• different clocks can give different answers for the same person;
• there is no agreed standard for validating them in individuals (Moqri et al., 2023);
• it is not yet proven that changing your clock score changes your actual risk.

Treat a consumer "biological age" result as a curiosity, not a diagnosis.

A practical testing plan

1. At home, yearly: VO2max estimate, resting heart rate, waist-to-height ratio, grip or sit-to-stand. Our healthspan checklist explains each test.
2. At home, regularly if raised: blood pressure.
3. With your doctor: ApoB or a lipid panel, HbA1c, and anything your history calls for. Athletes may want a few extra markers, see blood tests for athletes.
4. Optional: an epigenetic clock, if you're curious and can afford it.

Ignore any test that cannot change what you do. And discuss your results with a doctor, especially before acting on a borderline value. Our research page lists more of the studies behind these markers.

Sources

• Moqri M, Herzog C, Poganik JR, et al. Biomarkers of aging for the identification and evaluation of longevity interventions. Cell, 2023;186(18):3758-3775.
• Mandsager K, Harb S, Cremer P, et al. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw Open, 2018;1(6):e183605.
• Ettehad D, Emdin CA, Kiran A, et al. Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet, 2016;387(10022):957-967.
• Sniderman AD, Thanassoulis G, Glavinovic T, et al. Apolipoprotein B particles and cardiovascular disease: a narrative review. JAMA Cardiol, 2019;4(12):1287-1295.
• Selvin E, Steffes MW, Zhu H, et al. Glycated hemoglobin, diabetes, and cardiovascular risk in nondiabetic adults. N Engl J Med, 2010;362(9):800-811.
• García-Hermoso A, Cavero-Redondo I, Ramírez-Vélez R, et al. Muscular strength as a predictor of all-cause mortality in an apparently healthy population: a systematic review and meta-analysis of data from approximately 2 million men and women. Arch Phys Med Rehabil, 2018;99(10):2100-2113.
• Leong DP, Teo KK, Rangarajan S, et al. Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. Lancet, 2015;386(9990):266-273.
• Ashwell M, Gunn P, Gibson S. Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Obes Rev, 2012;13(3):275-286.
• Zhang D, Shen X, Qi X. Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis. CMAJ, 2016;188(3):E53-E63.
• Horvath S, Raj K. DNA methylation-based biomarkers and the epigenetic clock theory of ageing. Nat Rev Genet, 2018;19:371-384.