Illustration of the continuum of oxidative stress in health and pathology. The redox stress pathway emphasizes the signaling role of oxidative stress and focuses on reversible regulation and depends on the interaction between cellular components and the redox environment of the cell. In contrast, prolonged or high oxidative stress leads to structural changes in proteins, lipids, and DNA that are generally more irreversible. These represent two points along the continuum of how oxidative stress may contribute to aging phenotypes. Modified from Marcinek and Siegel .