Human life expectancy has steadily increased since the nineteenth century. Observations of supercentenarians and analyses of animal models of longevity suggest that lifespans can be extended through genetic or dietary modifications and it seems that there is no upper limit on Human Lifespan. However, evidence is controversial. Some researchers have noticed that the steady increase in life expectancy and maximum human lifespan seen during the last century will eventually stop.

Indeed, the age with the greatest improvement in survival got steadily higher since the early 20th century, but then started to plateau at about 99 in 1980. In the international databases of gerontology, scientists analysed the tendency of the maximum reported age of death in a given year in France, Japan, the United States and the United Kingdom which are the countries with the largest numbers of supercentenarians and observed a rapid increase between the 1970s and early 1990s and a plateau at 114.9 years in the mid-1990s.

The researchers observed the same trend when they considered the second, third, fourth and fifth oldest person who died in a given year.  It seems that there is a natural limit to human lifespan of about 115 years old. Lifespan is controlled by many genes and we could never modify it.