when the telomeres get too short, cell division—and thus cellular repair and renewal—stops. When DNA cells stop dividing, you don’t die immediately—the human body has around 10 trillion cells, each carrying DNA—although it’s well-established that people with short telomeres die younger than people with long telomeres. One leading hypothesis is that when telomeres shorten, and cells stop replicating, they enter a state of senescence and begin to gum up the works. But it is still not certain that the telomere shortening is the cause as opposed to simply a marker of trouble.
