Longevity · Explainer
Five Biomarkers Worth Tracking (and the Expensive Ones That Aren't)
The longevity industry sells hundred-marker panels. Most of what predicts how long you stay healthy is on a standard blood draw and a blood pressure cuff.
There is a growing market in expensive testing panels, biological-age scores and continuous monitoring. Very little of it changes what you would do. Here is the short list that does, roughly in order of how much evidence sits behind it.
1. Blood pressure
The most predictive number you can measure, the cheapest to measure, and the one most people ignore because it produces no symptoms until it produces a serious one.
Elevated blood pressure is a leading modifiable risk factor for cardiovascular disease and stroke worldwide. A home cuff costs about $40. Measure while seated, arm supported at heart height, after five minutes of sitting still, and take the average of two or three readings — a single reading in a clinic waiting room is a noisy measurement.
Diet, sodium, alcohol, bodyweight, sleep and aerobic exercise all move it. So do medications, which work well and are cheap.
2. ApoB (or at minimum, LDL-C)
Standard lipid panels report LDL cholesterol — LDL-C, the cholesterol carried by LDL particles. ApoB counts the particles themselves, and since each atherogenic particle carries exactly one ApoB protein, it is a more direct measure of how many of them are circulating and able to lodge in an artery wall.
Two people can share an LDL-C and differ substantially in ApoB. Where they differ, ApoB tends to be the better predictor of cardiovascular events. It costs a few dollars more than the standard panel and is not always ordered by default — it is usually worth asking for.
3. HbA1c
A rough average of your blood glucose over the previous two to three months, since it reflects how much glucose has bonded to your red blood cells over their lifespan. One draw, no fasting-window gymnastics, and much harder to game than a single fasting glucose.
It is the standard marker for identifying prediabetes and diabetes, and it moves with diet, bodyweight and activity.
4. VO2 max
Cardiorespiratory fitness is strongly associated with all-cause mortality, and the association is steepest at the bottom — the gain from being unfit to being moderately fit is larger than the gain from moderately fit to very fit.
A proper lab test involves a mask and a treadmill. A watch estimate is not accurate in absolute terms but is reasonable at tracking your own direction over months, which is the part you can act on. The intervention is aerobic training, and the largest returns are for the least active.
5. Grip strength
Strange-sounding and well supported. Grip strength is a proxy for total-body strength and neuromuscular function, and it predicts all-cause mortality and functional decline in older adults. A dynamometer costs about $25.
It is not that strong hands extend life. It is that grip tracks the muscle and strength you are carrying, and that is what determines whether you stay independent later. The intervention is resistance training.
The ones you can usually skip
- Biological-age scores. Different companies produce different ages for the same blood, and no one has demonstrated that chasing the number improves an outcome. Interesting, not yet actionable.
- Hundred-marker panels. More markers means more values sitting slightly outside a reference range by chance, which generates follow-up testing and anxiety without generating decisions. Reference ranges are built so that 5% of healthy people fall outside them.
- Continuous glucose monitors, for people without diabetes. Genuinely useful with diabetes. Without it, you mostly learn that eating raises your glucose and that the response is highly variable. Little evidence yet that acting on those wiggles improves anything.
- Full-body MRI screening. Finds a great many incidental findings that are harmless but require investigation to prove harmless.
Before you buy any supplement for this
Get the five numbers first. They tell you which lever, if any, is worth pulling, and several of them respond far more to sleep, alcohol, bodyweight and training than to anything sold in a bottle.
If a supplement claims to move one of these, that claim is now testable: measure, take it for three months, measure again under the same conditions. Very few products in this category invite that test.