Figure 1. Oxidative stress and oxidative eustress within redox biology.

Advances in oxidative stress and redox signaling have led to improved definitions for considerations in health and disease. Oxidative stress is defined in a pathologic sense, while physiologic oxidant production is termed oxidative eustress. Redox biology embraces the continuum of oxidation–reduction reactions in normal biology and pathology, including non-enzymatic as well as enzymatic reactions. This broader view recognizes that an individual has continuous environmental interactions that have major impact on health and disease.