Lifeboat Foundation

This is from 2014 but is getting posted around the past couple of days.

““It’s estimated that we’re born with around 20,000 blood stem cells, and at any one time, around 1000 are simultaneously active to replenish blood,” says Holstege. During life, the number of active stem cells shrinks, she says, and their telomeres shorten to the point at which they die –”

She lived to 115, but a study of Hendrikje van Andel-Schipper’s blood hints at factors limiting lifespan.