A new study indicates that the dramatic gains in life expectancy over the last two centuries are slowing down, with researchers suggesting a limit to how long people can live. The study, led by S. Jay Olshansky, highlights that while life expectancy improvements are still occurring, they are at a decreasing rate. The research focused on countries with the longest-living populations and found that the average improvement in life expectancy has dropped from 2.5 years per decade in the 1990s to 1.5 years in the 2010s. Experts agree that aging poses challenges to further increases in lifespan.