why some live longer

Living longer is one of the great goals of the science of aging. But a recent meta-analysis by researchers at the University of Sydney, published in the journal Biology Lettersissues an important warning: prolonging life does not mean that everyone benefits equally.

The study reexamined how three interventions – the dietary restriction and two drugs, rapamycin and the metformin– affect the age of death in vertebrates. The most striking finding is that, although two of the three treatments increased the average life expectancy, all three also increased the variance, that is, the difference between those who benefit the most and those who benefit the least.

The ideal in longevity research is not just that people live longer, but that More people reach old age in good healthwith less disparity between individuals. That is called “square the survival curve“What this meta-analysis demonstrates is that current interventions do not achieve that goal. Gains in average lifespan are accompanied by a proportional increase in variability. Some animals benefit a lot and others barely.

The researchers themselves are direct in their conclusions: “These approaches can prolong the lives of animals, but the benefits are not shared equally. Without more information, the result seems a biological lottery. “We are working to understand why, so that future longevity science is useful to everyone.”

The challenge, therefore, is not only to find interventions that extend life, but understand what factors determine who responds well to them and who doesn’t. Until science resolves that question, living longer will continue to depend, in part, on each person’s biology.