The telomere shortening theory of aging proposes that the gradual shortening of telomeres, the protective caps at the ends of chromosomes, contributes to the aging process. Telomeres naturally shorten with each cell division, and when they become critically short, cells enter a state of senescence or undergo programmed cell death (apoptosis). This process leads to a decline in tissue renewal and repair capacity. Factors such as chronic stress, oxidative damage, and inflammation can accelerate telomere shortening. Telomere length has been associated with aging and age-related diseases.