Background. Cardiovascular morbidity is a topical issue; stress is an essential contributing factor. Pathogenic links in damaging stress impact on the animal units of different reactivity is promising in disease prevention and development of individual correction methods. Objective. Stress-induced development of cardiovascular pathology is undeniable, the stress impact depending on individual systemic response, age and sex. Methods. 96 hypoxia high- and low-resistant (HR and LR, respectively) Wistar rats aged 5.5-6 months were used in experiments. Changes of lipid peroxidation processes, as well as protein oxidative modification, nitrite anion content and the indices of antioxidant defence under immobilizing stress were studied in the research. Results. Immobilizing stress causes the development of oxidative and carbonyl stress in HR and LR rats that is more pronounced in LR group; and the activation of antioxidant defence system. In males, stress development is concomitant with increased catalase activity as well as that of blood peroxidase, ceruloplasmin and reduced glutathione content, whereas increased catalase and ceruloplasmin activity has been found in HR females, and that of superoxide dismutase and ceruloplasmin – in LR group. As compared with the females, more intensive oxidative and nitroxidative stress, protein oxidative modification, and stress-related accumulation of circulating immune complexes have been found in the males. Conclusion. The most intensive oxidative and nitroxidative stress, protein oxidative modification, and stress-related accumulation of circulating immune complexes have been found in the hypoxia low-resistant males.