How much of our lifespan is down to good genetics? The answer: over half, according to research published in 2026. That’s a lot – 55 per cent to be exact.
Other, older studies have given widely varying estimates for the role of genetics. But if this one’s correct, it means the heritability of human lifespan is much higher than we previously believed.
What’s different about this paper is that the researchers – from the Weizmann Institute of Science, in Israel – controlled for external factors such as accidents, infectious diseases and living conditions, all of which cause premature death.
They believe that these factors “depressed” previous estimates of the genetic contribution, making it appear less significant than it truly is.
The potential finding could have implications for both longevity researchers and the average person who wants to eke out their time on Earth.
In the field of longevity, it’s thought that hundreds – possibly thousands – of genes play a role in lifespan. Assuming that’s true, then surprisingly few have been identified and confirmed by robust and replicated research.
Examples include the APOE gene, which affects cardiovascular health and the risk of neurodegenerative disease.
Another is FOXO3, which plays a varied and important role in energy metabolism, cellular health, immunity and inflammation. Variants of this gene show up regularly in people who live to 95 or beyond.
One emerging assumption in longevity genetics is that it’s genes like FOXO3 that are the most influential.
They’re not ‘longevity’ genes per se, but they are involved in the underlying systems and pathways that keep us healthy for longer (or shorter).
Of course, while your genes are hugely important, lifespan is not predestined and lifestyle factors that we all have control over also have a significant impact on how long we live.
This was demonstrated by a 2023 study in the UK, which found that switching from an unhealthy diet to eating patterns associated with longevity could increase a person’s lifespan by up to 10 years.
By the same token, research has shown that smoking can shorten a person’s life by 10 years. One 2024 study estimated that every cigarette costs 20 minutes of a person’s life.
Other factors regularly shown to affect your longevity are the ones we’ve all heard of, like physical activity, sleep quality, socioeconomic status, mental wellbeing and stress management, plus social connection and community.
A key area of study is epigenetics, which sits at the meeting point between genetics and lifestyle factors.
It’s the study of how behaviour and environment can affect the way our genes are expressed, and is sometimes described as the way lifestyle factors get ‘under the skin’.
In 2023, a landmark study in mice found that manipulation of the epigenome can drive mammalian ageing forwards or backwards.
As well as confirming the power that our lifestyles have, this research and other papers like it are prompting scientists to ask whether various markers associated with ageing can be reversed, including whether our very cells can be ‘reset’.
It’s no wonder the billionaires are so interested in longevity research.
This article is an answer to the question (asked by Morgan Cook, Hants) 'How much of our lifespan is down to good genetics?'
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