Antioxidants and oxidative stress in exercise

Strenuous exercise increases oxygen consumption and causes disturbance of i ntracellular pro-oxidant-antioxidant homeostasis, The mitochondrial electro n transport chain, polymorphoneutrophil, and xanthine oxidase have been ide ntified as major sources of intracellular free radical generation during ex ercise. Reactive oxygen species pose a serious threat to the cellular antio xidant defense system, such as diminished reserve of antioxidant vitamins a nd glutathione, and increased tissue susceptibility to oxidative damage, Ho wever, enzymatic and nonenzymatic antioxidants have demonstrated great adap tation to acute and chronic exercise. The delicate balance between pro-oxid ants and antioxidants suggests that supplementation of antioxidants may be desirable for physically active individuals under certain physiological con ditions by providing a larger protective margin.