Longevity — what the evidence actually says, and what you can change

Lifespan is how long you live. Healthspan is how long you live well — without the decade or so of illness, frailty and dependence that currently ends most lives. The gap between the two is the number this whole section is about, and the encouraging news from the large cohorts is that most of it is modifiable: cardiorespiratory fitness, muscle, sleep, metabolic health and the handful of blood markers that track them explain far more of the variance in how people age than their genes do.

Each article below takes one lever, names the evidence behind it — the study type, the cohort size, the trial — says what you can measure and how often, lists the mistakes we see most, and shows where the compounds in the research library, the goal pages in protocols and the clinic therapies honestly fit. Where the evidence is thin, the article says so. Where something is hype, it says that too.

The fourteen articles

How we grade the evidence on these pages

Where to start

If you have never measured anything: the biomarker panel, then VO2max, because it is the single strongest predictor and the one most people have never tested. If you are over 40 and tired: hormones after 40 and sleep — and read sleep first, because it is the cheaper fix. If you want to know whether rapamycin, metformin or an NAD drip is worth it: the longevity drugs and mitochondria. And if you want the whole thing turned into a plan: how we build one.