💀 The truth about life expectancy: why we won't live to 100 years

The dramatic progress in life expectancy observed during the 20th century in wealthy countries may well belong to the past. A recent study reveals that the pace of longevity gains has significantly slowed, calling into question optimistic projections about the future of human lifespan.

Conducted by researchers from several prestigious institutions, this analysis published in the Proceedings of the National Academy of Sciences relies on detailed demographic data and various mortality forecasting methods. The scientists examined the evolution of life expectancy in 23 high-income, low-mortality countries, using information from the Human Mortality Database. Their results indicate a clear deceleration of progress, with profound implications for society.


At the beginning of the 20th century, life expectancy increased by nearly five and a half months per generation, rising from 62 years for people born in 1900 to 80 years for those born in 1938. This rapid progress was largely due to medical advances and improvements in living conditions, which drastically reduced infant mortality. Industrialized countries benefited from major public health improvements, radically transforming longevity prospects in just a few decades.

For generations born after 1939, the pace of gains has slowed. None of the cohorts studied, including those born in 1980, will reach an average age of 100 years. We're talking about averages here - some individuals will exceed 100 years, but this will remain rare and exceptional as it is today. This observation is explained by the fact that previous gains were primarily driven by the decline in infant mortality, which is now so low that it offers little potential for further improvement. Future progress will need to come from better survival at advanced ages, but this will likely not be enough to compensate for the observed slowdown.

This study, while uncertain in the face of future contingencies such as pandemics or medical innovations, provides valuable data for planning healthcare systems and social policies. Governments and individuals may need to adjust their expectations and long-term strategies, taking into account a more moderate increase in life expectancy.

Life expectancy and its calculation

Life expectancy is a statistical measure that estimates the average number of years a person can expect to live, based on current mortality rates. It is often calculated at birth and varies considerably by region, era, and socioeconomic conditions.

To determine this value, demographers use life tables that record deaths by age in a given population. These tables allow for projecting mortality risks at each stage of life and deducing an average lifespan. Data often comes from national registries and international databases like the Human Mortality Database.

Life expectancy is not an individual prediction, but an average for an entire cohort. It can be influenced by various factors, such as medical advances, sanitary conditions, access to healthcare, and even natural disasters or conflicts. Understanding its evolution helps anticipate future needs in public health and retirement planning.

Over time, improvements in disease prevention and quality of life have led to significant increases, but as the study shows, these gains can slow when the most easily preventable causes of mortality are already under control.

Mortality forecasting methods

Mortality forecasting methods are statistical tools used to estimate how death rates will evolve in the future. They rely on historical data and mathematical models to identify trends and extrapolate possible scenarios.

Among common approaches are Lee-Carter models, which decompose mortality into age and time components, or cohort-based methods, which follow groups of people born in the same year. These techniques allow researchers to simulate various futures, taking into account factors such as medical progress or demographic changes.

While useful, these forecasts contain uncertainties, as they cannot anticipate all unforeseen events, such as sudden epidemics or major scientific discoveries. Researchers often use multiple methods to compare results and obtain a more robust view.

In the mentioned study, six different methods were employed to ensure the reliability of conclusions. This helps minimize biases and provide more accurate estimates for long-term planning of public and individual policies.