Hormesis

Hormesis is a biphasic dose-response phenomenon in which a low or moderate dose of a stressor produces a beneficial adaptive effect, while higher doses are harmful. Mild stressors such as heat, cold, exercise, fasting, or certain phytochemicals can involve activation of defence and adaptive pathways such as Nrf2, heat-shock proteins and AMPK in some settings, with the precise response depending on dose, tissue and context. In longevity research, hormesis is one mechanistic framework, alongside others, for why intermittent stress can extend healthspan in model organisms.