Telomeres, the repeated series of DNA sequences that cap the ends of linear chromosomes, become shorter during cell division and oxidative stress. Shortened telomeres have been documented in a wide variety of pathologies associated with aging and are also predictive of early mortality in the very old. However, telomere shortening--like the canary in the coal mine--is not the cause of the deleterious effects, but rather, the harbinger of increased health risk. Using immune responses to infection as a model system to further analyze the link between telomeres and age-related disease, we have demonstrated that the end-stage T cell with shortened telomeres is reduced in antiviral immune function and secretes large amounts of so-called proinflammatory factors. Our research has documented that maintaining high levels of the telomere-extending enzyme, telomerase, by either genetic manipulation or exposure of T cells to chemical telomerase activators, not only retards telomere loss but also restores a more youthful functional profile to the T cells. These observations suggest possible novel telomerase-based therapeutic approaches to enhancing healthspan in the elderly population.