Aqui está algo interessante e razoavelmente bem escrito!

Das várias teorias para a causa do envelhecimento, a do efeito dos telómeros é das mais conhecidas e comummente aceites.

Telomeres are the protective caps at the ends of chromosomes in cells. Chromosomes carry the genetic information. Telomeres are buffers. They are like the tips of shoelaces. If you lose the tips, the ends start fraying.
Telomerase is an enzyme. In cells, it restores the length of the telomeres when they get worn. As the ends of the chromosomes wear down, the telomerase comes in and builds them back up.
In humans, the thing is that as we mature, our telomeres slowly wear down

Segundo esta teoria, o encurtamento dos telómeros faria com que ocorressem danos no código genético, causando alguns dos sintomas próprios da idade. 

Ainda que, pessoalmente, acredite que o envelhecimento resulte de vários processos e não determinantemente apenas do comprimento dos telómeros, um dos aspectos fundamentais deste artigo, é, para mim, a afirmação da influência indirecta do ambiente sobre os genes – o stress levaria a um encurtamento dos telómeros

In my lab, we’re finding that psychological stress actually ages cells, which can be seen when you measure the wearing down of the tips of the chromosomes, those telomeres.
This was the first time you could clearly see cause and effect from a nongenetic influence. Genes play a role in telomerase levels, but this was not genes. This was something impacting the body that came from the outside and affecting its ability to repair itself.

We’ve been collaborating on studies looking at the telomerase levels in people who practice meditation. We are looking at whether or not telomerase changes after a three-month program of meditation.

Ahummmmmmmm