Exercise and Oxidative Stress

Journal of Exercise Nutrition & Biochemistry 1998;2(1):1-24.

Abstract

The oxygen molecules are required for the aerobic metabolism organ to produce the energy, but in the process of producing the oxygen metabolism the intermediate metabolism by-products which has toxicity on a living body can be produced. Substances which have toxicity are superoxide radical (O_2^-·), hydrogen peroxide (H_2O_2) and singlet oxygen (^1O_2), but among these substances, superoxide radical has one more electron of the oxygen molecules in the form of anion which plays an important role. There are several mechanisms that can potentially lead to enhanced reactive oxidative species(ROS) formation during an exercise induced oxidative stress, and that include mitochondrial origin, endothelial origin, inflammatory origin, catecholamine origin. The generation of ROS or free radicals may play an important role in the initiation and promotion of degenerative conditions. ROS are initially generated by the univalent reduction of oxygen, producing superoxide anion(O_2^-·) SOD removes O_2^-· by catalyzing a dismutation reaction, involving oxidation of one O_2^-· to oxygen and reduction of another O_2^-· to hydrogen peroxide. catalase(CAT) reduces H_2O_2 to water and oxygen. Glutathione peroxidase(GPX) is generally considered the most prominent defense against H_2O_02. The scavengers in the form of molecules that can react with radical, include ascorbate, vitamin E and C, β-carotene as well as sugars, unsaturated amino acids and fatty acids. SOD is inhibited by H_2O_2, catalase and GPX by superoxide. Therefore, it is not surprising that numerous studies conducted during the past two decades have demonstrated elevated levels of lipid peroxide by-products following acute physical activity in various species. Most studies support the contention that during strenuous exercise, generation of reactive oxidative species is elevated to level that overwhelms antioxidant defense system.