Mild Stress in the Aging Heart: Role of Ischemic Preconditioning

Hormetic effects have been documented in diverse combinations of stressors and recipient organism. Such sublethal stress pre-treatments have been shown to increase stress resistance and life expectancy in several animal organisms. Stressors reported to increase subsequent stress resistance include heat, cold, hypergravity, and pesticides. Increased life span has been reported after a similarly diverse number of hormetic treatments including heat, cold, hypergravity, ionizing radiation, exercise, electric shock, and wounding accompanied by regrowth (Martinez 1996; Minois 2000). Khazaeli et al. (1997) have demonstrated that heat induced longevity extension in Drosophila and, similarly, Michalski et al. increased longevity in Caenorhabditis elegans by heating stress (2001). Resistance to the paradoxical effects of hormesis necessitated the extended and exhaustive documentation of the phenomenon, an effort led primarily by Edward Calabrese (Kaiser 2003). Those efforts produced both practical and theoretical benefits. The practical benefit was an additional set of tools useful in studying survival, following the application of mild stress. The theoretical aspect was further support for the inverse correlation observed between stress resistance generally and improved survival.