Since the 19th century, the average life expectancy for humans has increased. Scientific advances in public health, diet, environment and medicine have served to lengthen our lives from an average of 47 years in 1900 to nearly 79 years today. But now science is telling us that the party is over: humans have reached their maximum age – 115 years – and no medical advances are likely to extend it any further.

“Demographers as well as biologists have contended there is no reason to think that the ongoing increase in maximum lifespan will end soon,” said senior author Jan Vijg, PhD, professor and chair of genetics and professor of ophthalmology & visual sciences at the Albert Einstein College of Medicine. “But our data strongly suggest that it has already been attained and that this happened in the 1990s.”

The researchers came to their sobering conclusions after examining data from the Human Mortality Database. The HMD began life as an extension of earlier projects in the Department of Demography at the University of California, Berkeley, and at the Max Planck Institute for Demographic Research in Rostock, Germany. It is currently maintained by American and German teams of scientists, and includes records from over 40 countries.

Although the number of people who survive to old age (here defined as 70 and above) has been steadily increasing since 1900, the data shows diminishing returns for people surviving past 100 years old. The ages of society's elite “Over 100 Club” – the supercentenarians – increased steadily until around 1995, at which point they started to plateau. This coincided with the death of a 122-year-old French woman who achieved the maximum documented lifespan of any person in history.

The researchers now calculate that the average maximum human lifespan is – and will be – 115 years. The estimate the probability of anyone living to 125 to be less than 1 in a thousand.

“Further progress against infectious and chronic diseases may continue boosting average life expectancy, but not maximum lifespan,” said Dr. Vijg. “While it’s conceivable that therapeutic breakthroughs might extend human longevity beyond the limits we’ve calculated, such advances would need to overwhelm the many genetic variants that appear to collectively determine the human lifespan. Perhaps resources now being spent to increase lifespan should instead go to lengthening healthspan – the duration of old age spent in good health.”

The research has been published in Nature.