摘要：Reactive oxygen species (ROS) are formed during the normal metabolism, and continually cause cell damage. The main antioxidant defense system is constituted by antioxidant enzymes as superoxide dismutase, catalase and glutathione peroxidase. Physical exercise is a condition that influences the balance between oxidative attack and antioxidant defense mechanisms. To protect the tissues against possible damages caused by ROS, the antioxidant enzymes seem to adapt, increasing their activities in trained individuals. Many studies involving oxidative stress and exercises have been conducted in animal models, especially the rat. However, most of these studies are criticized, because few associate the metabolic variables to the intensity of the effort experienced by the animal during the exercise.
