Long telomeres extend lifespan

Myth

Telomeres are the “molecular clocks” of aging. People with longer telomeres live longer, and interventions that lengthen telomeres will extend human lifespan. A related myth holds that aging begins when telomeres are completely depleted and chromosomes start losing essential DNA—this catastrophic endpoint supposedly drives cellular dysfunction and death.

Reality

Shorter telomeres are a lifespan-increasing adaptation in large mammals including humans. Complete telomere depletion does not occur in normal human aging—cells typically senesce or die when telomeres reach 5-15% of their original length, with substantial telomeric DNA remaining. In humans and other large mammals, extremely long telomeres increase cancer risk