Glossary
Oxidative stress.
Direct answer
Oxidative stress describes an imbalance between reactive oxygen species and the capacity of a cell to neutralise them and repair damage. When the balance tips the wrong way, membrane fats, proteins and genetic material are altered. The term names a state, not a disease and not a single measurement.
Oxidative stress is often treated as a synonym for damage. The accurate picture is a shifted balance: reactive molecules belong to normal metabolism and act as signals. Measurement is the second trap. Blood markers give an overall view rather than the situation in one tissue, and they move with exercise, feeding and time of day.
In horses the link with exercise is central. Under work, equine muscle cells consume very large amounts of oxygen, and production of reactive species rises accordingly. The resulting shift is part of the training stimulus and triggers adaptation. Reading it automatically as damage erases the difference between stimulus and overload.
Reactive oxygen speciesHormesisHomeostasisChronic inflammation
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