Hormesis is the dose-response phenomenon where low-to-moderate stress produces beneficial adaptation, while high-dose stress damages.
Mechanism — Mild stressor activates Nrf2, sirtuins, heat shock proteins, autophagy, and mitochondrial biogenesis — adaptive responses that prepare cells for future stress. Exercise, cold exposure, heat, fasting, and certain phytochemicals all work via hormetic pathways.
Use case — Adopt one hormetic stressor at a time, build tolerance, then layer. Zone 2 + Zone 5 cardio, resistance training, sauna, cold plunge, fasting, polyphenols.
Caveats — Dose matters — the same stress that benefits at moderate amounts harms at high. Insufficient recovery turns hormesis into chronic stress. Track recovery markers (HRV, sleep, mood, performance) to stay in the beneficial dose range.