Despite Medical Advances, Life Expectancy is Only Increasing Slowly

In the 19th and 20th centuries, life expectancy increased dramatically thanks to healthier diets, medical advances and many other improvements in quality of life. However, after almost doubling during the 20th century, the rate of increase has slowed considerably over the past three decades, according to a new study led by the University of Illinois at Chicago. Despite numerous medical and public health breakthroughs, life expectancy at birth in the countries with the highest life expectancy has increased by only an average of six and a half years since 1990, according to the analysis. This rate of improvement is far below some scientists’ expectations that life expectancy would increase faster this century and that most people born today would live to be over 100 years old.

Prolonging Life Expectancy Can be Harmful

The Nature Aging publication “Implausibility of Radical Life Extension in Humans in the 21st Century” provides new evidence that humans are approaching a biologically determined limit to life. The greatest advances in life expectancy have already been achieved through successful efforts to combat disease, according to lead author S. Jay Olshansky of the UIC School of Public Health. This leaves the harmful effects of aging. Most people living to older ages today are living in a time created by medicine. But these medical plasters add fewer years to life, even if they are occurring at an accelerated pace, meaning the period of rapid gains in life expectancy is now demonstrably over, according to Olshansky. It also means that further extending life expectancy by reducing disease could be harmful if those extra years are not healthy years. According to the researcher, the focus should now shift to measures that slow the aging process and extend the health span. The health span is a relatively new metric that measures the number of years a person is healthy, rather than just alive.

The analysis, conducted in collaboration with researchers from the University of Hawaii, Harvard University and the University of California, Los Angeles, is the latest chapter in a three-decade-long debate about the potential limits of human longevity. In 1990, Olshansky published a paper in the journal Science arguing that human life expectancy had reached a ceiling of around 85 years and that the greatest advances had already been made. Others predicted that advances in medicine and public health would accelerate 20th-century trends into the 21st century.

Thirty-four years later, the findings reported in the 2024 Nature Aging study support the notion that the increase in life expectancy will continue to slow as more and more people face the harmful and unchangeable effects of aging. The study examined data from the eight countries with the highest life expectancy and Hong Kong, as well as from the United States – one of only a handful of countries where life expectancy fell during the period under review.

Improving Quality of Life in Old Age, Rather than Extending it

This finding refutes the conventional wisdom that our species’ natural longevity is still ahead of us – a lifespan longer than today’s levels – and instead is behind us, somewhere in the range of 30 to 60 years. Researchers have now proven that modern medicine is making smaller and smaller improvements in longevity, although medical progress is advancing at breakneck speed. Although more people may live to be 100 or older in this century, these cases will remain exceptions that will not significantly increase average life expectancy, according to experts.

This conclusion is directed against products and industries, such as insurance and asset management companies, that are increasingly based on the assumption that most people will live to be 100. However, the results do not rule out the possibility that medicine and science can bring further benefits. The authors argue that there may be more immediate potential to improve the quality of life in old age rather than to prolong life. More investment should be made in geroscience – the biology of ageing – which may hold the seeds for the next wave of health and life extension. According to the researchers, there is plenty of room for improvement: reducing risk factors, addressing inequalities and promoting healthier lifestyles can all help people live longer, healthier lives.