Your Genes Control More of Your Lifespan Than Scientists Thought—Here's What That Means

For decades, scientists have debated how much of our lifespan comes down to the genes we inherit versus the choices we make. A groundbreaking new analysis just shifted that conversation dramatically. Researchers have discovered that about 55% of the variation in human lifespan is heritable—meaning genetics plays a much larger role in how long we live than anyone previously thought.

This finding is a major departure from earlier estimates, which suggested that only 10–25% of lifespan differences were attributable to genetics. The new research, published in the journal Science, challenges decades of scientific consensus and opens exciting new doors for understanding aging and developing treatments for age-related diseases.

Why Were Previous Estimates So Far Off?

So what changed? The research team, led by biophysicist Ben Shenhar at the Weizmann Institute of Science in Israel, says the problem with older studies was that they didn't properly separate two very different types of factors affecting lifespan. Previous research lumped together deaths caused by external factors—like infectious diseases or accidents—with deaths caused by internal biological processes, such as the gradual decline of organ function from DNA damage over time.

"There is much to be learnt from the genetics of ageing, if we can understand what genes are responsible for healthy ageing," Shenhar explains. By teasing apart these different causes of death, the new analysis revealed that genetics actually has a much stronger influence on longevity than previously recognized.

How Did Researchers Reach This Conclusion?

To uncover this hidden genetic influence, Shenhar and his colleagues re-examined historical data stretching back to the 1800s from twin studies conducted in Denmark and Sweden, as well as studies on siblings of centenarians in the United States. Twin studies are particularly powerful for understanding genetics because identical twins share 100% of their DNA, while fraternal twins and other sibling pairs share about half on average. By comparing how similar their lifespans were, researchers could calculate how much genetics versus environment mattered.

What Does This Mean for You?

The takeaway isn't that your genes are destiny. Even though genetics accounts for 55% of lifespan variation, that still leaves 45% influenced by factors within your control—your diet, exercise habits, stress levels, sleep quality, and lifestyle choices. The new findings simply mean that understanding the genetic basis of aging could help scientists develop better treatments and interventions for age-related diseases.

For people interested in longevity, this research suggests that while you can't change your genes, learning more about them could help you make smarter health decisions tailored to your genetic predispositions. As scientists continue to identify specific genes responsible for healthy aging, personalized approaches to staying young and vibrant may become increasingly possible.