How much of ageing is genetic?
"It runs in my family" is the most common reason people decide none of this is worth doing. The estimates do not support it — and the parts that genuinely are genetic are mostly identifiable, which changes what you do rather than whether you bother.
The heritability estimates
Twin studies have historically put the heritability of lifespan at roughly 20–30%. Later analyses using very large pedigrees suggested the true figure is lower still — possibly under 10% — because people tend to marry partners resembling themselves, which inflates apparent heritability in family data.
Either way, the large majority of variation in how long and how well people live is not explained by inherited genetics. That is the single most useful fact in this area and the least widely known.
Families share more than genes
Diet, smoking, activity, alcohol, body composition, sleep habits and attitudes to medical care all run in families without being inherited. A family history of early heart disease may be transmitting a dietary pattern as much as a genotype.
This is not a reason to dismiss family history — it is genuinely predictive and should raise your urgency. It is a reason not to read it as a verdict.
The genetics that do matter are specific
Lp(a) is the clearest example: largely genetically determined, barely responsive to lifestyle, and a strong independent risk factor. It is also measurable with a single ordinary blood test that almost nobody is offered.
Familial hypercholesterolaemia affects roughly 1 in 250 people and is substantially underdiagnosed. APOE status affects both lipid handling and Alzheimer's risk. Haemochromatosis is common, genetic, and entirely treatable once identified.
Each of these is actionable precisely because it is specific. Knowing you carry high Lp(a) does not mean nothing can be done; it means everything else — ApoB, blood pressure, smoking — should be managed more aggressively, because your baseline risk is higher.
What this means in practice
Measure the genetic factors that are measurable, once: Lp(a), and a lipid panel that would reveal familial hypercholesterolaemia. Those two tests resolve most of the genuinely inherited cardiovascular risk that matters.
Treat the rest as modifiable until proven otherwise, because for the large majority of variation it is. A family history should change your threshold for acting, not your assessment of whether acting works.
Score yourself free — no account needed →Frequently asked questions
Is aging genetic?
"It runs in my family" is the most common reason people decide none of this is worth doing. The estimates do not support it — and the parts that genuinely are genetic are mostly identifiable, which changes what you do rather than whether you bother.
What does this guide cover?
This guide covers: The heritability estimates; Families share more than genes; The genetics that do matter are specific; What this means in practice.