New study shows up to 55% of human lifespan could be influenced by genes, reshaping how we think about aging and longevity.
For as long as we can remember, the advice has been the same. Eat right, exercise, don’t smoke. Eat healthy, do some physical activities, don’t drink too much alcohol. Follow the rules, and maybe you’ll live longer. But what if there’s a piece of the puzzle we’ve been underestimating all along?
A new study published in Science suggests that genetics may have more say over our lifespan than we thought – up to 55% [1]. That’s more than half of the story. Researchers studied twins across decades, carefully separating deaths caused by accidents or infections from those linked to natural aging and chronic disease. By removing this “outside noise,” they could see the real influence of DNA on how long we live.
Why twins? Because identical twins share the same DNA. When scientists compare them, they can see how much of the lifespan is tied to genes versus environment.
“The number that we got is not out of nowhere,” Ben Shenhar, lead author and aging researcher at the Weizmann Institute of Science in Israel told USA Today. “If you look at twin studies on pretty much anything in humans, you get this 50%. Even the age at menopause – a classic marker of aging – has a similar genetic footprint [2].”
Morten Scheibye-Knudsen, from the University of Copenhagen, calls this method a way to cut through “outside noise.” He explains that while humans live a maximum of 120 years, yeast cells only survive for 13 days and bowhead whales can live for 200 years. He suggests that these variations prove our genes have already established a general limit on our lifespan, meaning behavior cannot account for everything.
Now, before anyone decides genetics is destiny, there’s a silver lining. While DNA may account for about 55% of lifespan, the remaining 45% is influenced by diet, exercise, habits and the environment.
Dr Eric Verdin, CEO of the Buck Institute for Research on Aging, cautions that it is misleading for people to assume their genes alone dictate how long they will live [2].
Shenhar concurs, explaining that while genetics might establish a baseline for longevity, lifestyle factors, such as maintaining a healthy diet, staying active and avoiding bad habits, can still significantly influence the final outcome.
It’s like a garden. Your genes are the soil and sunlight, but how you tend to the plants – the water, pruning, fertilizer – determines whether they flourish.
The study also supports earlier findings: people who reach 100 often carry protective genes that lower their risk of chronic disease. Genes like FOXO3, APOE and SIRT6 have been linked to longevity, but researchers believe many more work together quietly in the background.
“It’s not about clawing your way to 100,” Shenhar says. “These people have genes that actively protect against the harms of aging [2].”
This isn’t just trivia on longevity. Knowing how much our DNA shapes lifespan could guide the next generation of therapies and health strategies. If we can identify protective genes and understand how they interact, we can tailor interventions to complement lifestyle and environmental factors.
Scheibye-Knudsen noted that while genetics establishes certain boundaries, there is significant potential within those constraints to enhance health and prolong a person’s healthy years. He further characterized this pursuit as the most compelling frontier in current longevity research.
So while genetics may set the stage, we’re not simply actors following a script. The story of our lifespan is still being written, one choice, one therapy and one discovery at a time.
[1] https://www.science.org/doi/10.1126/science.adz1187
[2] https://www.usnews.com/news/health-news/articles/2026-02-02/study-finds-genetics-may-shape-up-to-55-of-how-long-you-live
