Longevity medicine has an image problem. For every serious physician working on healthspan, there is a clinic selling “biological age” scores, IV drips and supplement stacks of dubious value. Underneath the noise, though, sits a genuinely useful idea: a small set of measurable markers predicts how well you are likely to age — and most of them respond to things you can actually change.
Here is a sober tour of the biomarkers with real evidence behind them after 40, and how to think about tracking them.
What makes a biomarker worth tracking?
Three tests, borrowed from how evidence-based physicians evaluate any screening tool:
- It predicts outcomes. The marker is associated with cardiovascular disease, cancer, dementia or mortality in large, long-term studies — not just in a rodent or a podcast.
- It changes management. Knowing the number leads to a decision you would not otherwise make.
- It responds to intervention. There is evidence that improving the marker improves the outcome — not merely that the two travel together.
Fashionable tests usually fail one of these. The classics below pass all three.
The cardiovascular core
ApoB (or at minimum, a proper lipid panel)
If you track one marker for longevity, make it this one. ApoB counts the number of atherogenic particles in your blood — the particles that, over decades, build the plaques behind heart attacks and strokes. The evidence linking lower lifetime ApoB to lower cardiovascular risk is about as strong as observational and genetic science gets. Many longevity-minded physicians now treat ApoB as the primary lipid target, with LDL cholesterol as its more familiar proxy. Standard lipid panels are a reasonable start; ApoB adds precision, particularly when triglycerides are elevated.
Blood pressure
Unfashionable, unprofitable, and one of the most powerful longevity interventions in existence. Hypertension drives stroke, heart failure, kidney disease and vascular dementia, usually silently. Home monitoring with a validated cuff, done properly (seated, rested, both arms initially), beats occasional clinic readings.
Coronary artery calcium (CAC) — once, at the right time
Not a blood test but a low-radiation CT scan that detects calcified plaque. For people at intermediate risk around mid-life, a CAC score meaningfully refines whether statins and aggressive prevention make sense. A score of zero is genuinely reassuring; a high score reframes the next decade of prevention. It is a one-off decision tool, not an annual ritual.
Metabolic health
HbA1c and fasting glucose
HbA1c reflects average blood sugar over roughly three months. Prediabetes affects a large share of adults over 45, most of whom do not know it — and it is largely reversible with weight, movement and sleep changes when caught early. Some clinicians add fasting insulin or an oral glucose tolerance test for a fuller picture, since glucose rises late in the process while insulin rises early.
Body composition, not weight
Muscle is a longevity organ. Grip strength and muscle mass predict disability and mortality in older age better than BMI does. A DEXA scan or even consistent waist measurement plus strength benchmarks tells you more than the scale. The goal after 40 is not to weigh less; it is to keep muscle and lose visceral fat — the fat packed around organs that drives inflammation and insulin resistance.
Inflammation and organ function
hs-CRP
High-sensitivity C-reactive protein is a marker of chronic low-grade inflammation, which sits upstream of cardiovascular disease and is associated with faster biological ageing. It is cheap and useful as a trend, though a single elevated reading often just means you had a cold — repeat it before interpreting.
Kidney and liver function (eGFR, ALT, GGT)
Neither glamorous nor optional. Kidney function declines quietly with age and interacts with blood pressure and diabetes; liver enzymes catch fatty liver disease, now epidemic and usually silent. These come free with any standard panel.
The fitness markers
VO2max
Cardiorespiratory fitness is among the strongest known predictors of all-cause mortality — in several large analyses, low fitness rivals or exceeds smoking as a risk factor. A laboratory VO2max test is the gold standard; a well-chosen submaximal test or even a timed walk gives a usable estimate. Unlike most blood markers, this one improves only through training, which is rather the point.
Resting heart rate and heart rate variability
Accessible via any decent wearable, and meaningful as long-term trends rather than daily verdicts. A falling resting heart rate over months usually reflects improving fitness and recovery.
What about “biological age” clocks?
Epigenetic clocks and commercial biological-age scores are scientifically fascinating and clinically premature. Different clocks give different ages for the same person on the same day, and we do not yet know whether improving a clock score improves outcomes. Treat them as entertainment with a research future — not as a basis for decisions or for buying interventions.
A sensible tracking rhythm
More measurement is not more prevention. A reasonable cadence for a healthy adult over 40:
- Annually: blood pressure, lipid panel (ideally with ApoB), HbA1c, kidney and liver function, hs-CRP, waist and strength benchmarks. A well-designed executive check-up covers exactly this layer.
- Every 1–3 years: fitness testing, body composition, thyroid function, vitamin D if previously low.
- Once, timed with your physician: CAC scoring, baseline DEXA.
- Per guidelines: cancer screening appropriate to your age, sex and family history.
Everything else should be added because your history suggests it — not because a package includes it.
The uncomfortable truth
The markers above mostly point at the same levers: move more, lift something, sleep enough, do not smoke, eat like a Mediterranean grandmother, manage blood pressure and lipids early. Longevity medicine at its best is not a bypass around these fundamentals; it is a system for measuring whether yours are working, and catching the exceptions early.
If you would like help building a sensible, evidence-based screening plan — or arranging one in Barcelona with results explained in your language — that is our daily work at Vensavita. The first conversation is free. And as always, interpret your numbers with a physician who knows your full history, not with an article — this one included.