72 is the new 30: the stunning speed of our longevity gains

A revolutionary leap

Human longevity has improved so rapidly over the past century that 72 is the new 30 — at least in the evolutionary sense. That was the conclusion of a study by Oskar Burger, Annette Baudisch, and James Vaupel of the Max Planck Institute for Demographic Research, published in the Proceedings of the National Academy of Sciences in October 2012.

The researchers compared the mortality of today's lowest-mortality populations (Sweden and Japan) with the evolved human mortality profile — estimated from ethnographically observed hunter-gatherers — and found the difference to be greater than the difference between hunter-gatherers and wild chimpanzees. Astonishingly, the bulk of this mortality reduction has occurred since 1900: roughly four of the 8,000 human generations that have ever lived.

Equivalent ages

The team's concept of "ages of equivalent mortality" makes the point vividly: a hunter-gatherer at age 30 faced the same probability of death as a present-day Japanese person at age 72. A 15-year-old wild chimp has about a 4.7% annual chance of dying — a hunter-gatherer faces that risk at age 63, while a 15-year-old hunter-gatherer's 1.3% annual risk is what a Swede faces at 69.

Even at 1900, Swedes were closer in mortality to hunter-gatherers than to Swedes today. The gap between 1900 and today — a "rapid revolutionary leap" — is far greater than the gap between hunter-gatherers and chimps.

Why it happened — and why nobody predicted it

The researchers found that hunter-gatherers were about 100 times more likely to die before age 15 than today's Japanese or Swedes. Burger attributed the explosion to unglamorous fundamentals: antibiotics and vaccines, huge gains in agricultural productivity that made food abundant, and widespread clean water. Notably, the rise in human longevity over the past century outpaced what scientists achieved in lab experiments breeding long-lived fruit flies — and it wasn't genetic at all.

"I still can't believe how recent most of the progress is," Burger said. Human mortality, he added, has shown itself to be far more "plastic" — capable of manipulation — than anyone had imagined, casting doubt on the idea of a fixed "wall of death" set by aging genes.

The open question

The study deliberately avoided asking whether extending life indefinitely is moral or desirable, or whether the extra years can be enjoyed in good health. But it did raise an economic alarm: industrialized economies built their pension systems for much shorter lives and now face the cost of supporting so many people for so long.

Archive summary, February 2013. The study: Human mortality improvement in evolutionary context (PNAS 109:18210–14).