The right answer is slowly erode their chromosome ends.
Telomerase is an enzyme found in eukaryotic organisms, which, during DNA replication, has the mission to dress the telomere chromosomes, nucleotide sequences placed at their ends and used to preserve them.
Telomerase expresses itself very little (if at all) in differentiated cells. By dint of cellular divisions, the telomeres disappear, the chromosomes are damaged and the cell returns to senescence. In contrast, the enzyme is very active in germ lines. It therefore prevents aging stem cells. It is considered that it could be one of the levers to activate to curb or even stop aging.