Genetics Play Bigger Role in Longevity Than Lifestyle, Study Finds

Researchers say inherited factors explain over half of lifespan differences, challenging earlier estimates.

Feb. 1, 2026 at 3:55pm

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A new study published in Science suggests that genetics play a much larger role in determining lifespan than previously thought, with inherited factors accounting for over 50% of variations in how long people live. The research, led by Uri Alon of Israel's Weizmann Institute of Science, analyzed mortality data from Swedish twins, Danish twins, and US siblings of centenarians to isolate the effects of aging itself, rather than deaths from accidents or infections. The findings challenge earlier estimates that genetics only account for 25% or less of lifespan differences, with the authors estimating that healthy or unhealthy habits can only shift life expectancy by around 5 years in either direction.

Why it matters

This study has significant implications for how we think about longevity and the factors that influence it. If genetics play such a dominant role, it may mean that individual lifestyle choices are less impactful than previously believed when it comes to achieving extreme old age. The findings could reshape public health messaging around longevity and challenge the notion that people have full control over their lifespan through diet, exercise, and other lifestyle factors.

The details

The researchers used mortality data from Swedish twins born between 1900 and 1935, as well as Danish twins born earlier and US siblings of centenarians, to try to isolate the effects of aging itself rather than deaths from accidents or infections. After accounting for these non-aging-related deaths, the team found that inherited factors explained over 50% of the variations in lifespan, far exceeding earlier estimates of 25% or less. Lead researcher Uri Alon estimates that healthy or unhealthy habits can only shift life expectancy by around 5 years in either direction.

  • The study was published on February 1, 2026 in the journal Science.

The players

Uri Alon

A researcher at the Weizmann Institute of Science in Israel and the lead author of the study.

S. Jay Olshansky

An epidemiologist who was not involved in the research but commented on the findings.

Daniela Bakula

A researcher at the University of Copenhagen who says the findings match what's known in other species, where lifespan is strongly genetic.

Bradley Willcox

A geriatrician at the University of Hawaii who argues it's impossible to cleanly separate "intrinsic" biological causes of death from environmental ones.

Thomas Perls

The director of the New England Centenarian Study at Boston University, who says family history looms large when it comes to reaching 95 or 100 years old.

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What they’re saying

“You don't have as much control as you think”

— S. Jay Olshansky (New York Times)

“If your genetic "ceiling" is about 80, for example, you might push that to around 85 with ideal habits—or cut it to 75 with none”

— Uri Alon, Researcher, Weizmann Institute of Science (New York Times)

“Even for the genetically fortunate, it's easy to shorten your life but very difficult to lengthen it.”

— S. Jay Olshansky (New York Times)

What’s next

Researchers plan to further investigate the complex interplay between genetics, lifestyle, and longevity in future studies.

The takeaway

This study challenges the widely held belief that individual lifestyle choices are the primary determinant of lifespan, suggesting that genetics play a much more significant role than previously thought. The findings could prompt a rethinking of public health strategies and messaging around longevity.