Among the most important pathogenetic mechanisms of the body's homeostasis disorders are oxidative and nitrosive stress caused by the excessive formation of free radicals and active forms of nitrogen, which are strong oxidants and are capable of damaging vital molecules such as enzymes, proteins, membrane phospholipids, nucleic acids. Their sources are different, the list of pro-oxidants includes dietary defects, psychoemotional and stress [1].
The influence of inadequate physical activity on the body can violate the metabolic status, which is caused by the activity of metabolic processes. The products of incomplete metabolism accumulating in this case lead to disruption of the detoxification and antioxidant defence systems of the body [2, 3]. This concerns the hypothalamic-pituitary-adrenal system, activation of oxidative degradation of lipids occurring under the action of free radicals [4], i.e. oxidative stress develops [57]. Violation of lipid peroxidation intensity can distort the speed and direction of a large number of various biochemical reactions in the human body.
One of the leading systems that neutralize the products of lipid peroxidation is the antioxidant system, which includes glutathione-dependent enzymes (glutathione transferase, glutathione peroxidase, glutathione reductase). The first catalyzes the reactions of neutralization of free radicals, which occur with the participation of glutathione, the second restores oxidized hydrogen molecules, lipid and other organic molecules oxidized by oxygen radicals. Glutathione reductase restores glutathione itself. In all of these enzymatic reactions, glutathione acts as a coenzyme. Reduced glutathione has its antioxidant activity, in the course of its antioxidant and detoxification functions, it is converted into an oxidized form [1].
The nitric oxide system is a regulator of many physiological and biochemical processes in the human body [8]. Nitric oxide is an active, short-lived radical (the life period is from 3 to 50 seconds). The biological effect mediated by this molecule depends on its interaction with a particular chemical group. On the one hand, nitric oxide has a positive effect on the regulation of vascular tone, contributing to effective vasodilation under intense loads, it increases maximum muscle strength in trained athletes [9, 10]. On the other hand, NO molecules can interact with active forms of oxygen, thus turning into active forms of nitrogen. The reaction of nitric oxide with the superoxide anion (O2) leads to the formation of a highly reactive oxidant - peroxynitrite (ONO), which can interact with many biomolecules, thereby mediating the toxic effect of NO [8].