Measure — but read it right
Biomarkers are measurable signals of what is happening in the body — from blood tests to fitness measures to hormone panels. They are genuinely useful, turning vague notions of health into something you can track, but each describes risk or state at the population level rather than destiny for one person. Useful use means tracking the signal without mistaking it for destiny.
Cholesterol and ApoB
Blood lipids are among the best-established cardiovascular markers. ApoB counts the number of atherogenic — artery-damaging — particles directly, and reviews argue it captures cardiovascular risk more precisely than LDL-cholesterol concentration alone, because it is the particle number that drives the disease process.
Blood sugar: glucose, HbA1c and CGM
Glucose can be measured as a fasting snapshot, as HbA1c (a rough three-month average reflecting glucose bound to haemoglobin), or continuously with a wearable sensor. Continuous glucose monitoring adds the pattern — how glucose moves across a day — and international consensus defines interpretation targets such as time in range, though those were established for diabetes management rather than for optimisation in healthy people.
Inflammation markers
Chronic low-grade inflammation — “inflammaging” — is a recurring theme in ageing, and it can be indexed by blood markers such as C-reactive protein and inflammatory cytokines. No single marker captures it cleanly, and reviews on assessing inflammaging stress that these are population-level signals rather than precise personal gauges.
Performance markers: VO₂ max, strength and body composition
Functional measures are among the strongest predictors of long-term outcomes. VO₂max — aerobic fitness — is repeatedly associated with mortality, and even grip strength, a simple proxy for whole-body strength, predicts cardiovascular and all-cause outcomes in very large cohorts. Body composition (the muscle-to-fat ratio) carries more information than weight or BMI alone.
Biological age, and the limits of tracking
A fast-moving area tries to estimate biological age directly — most prominently through “epigenetic clocks” that read age-associated DNA-methylation patterns. These are promising for evaluating whether an intervention actually moves ageing, but they are still being validated, and their use as a personal readout runs ahead of the evidence. Biomarkers, wearables and clocks support informed tracking — not certainty about any one person.
