Oxidative stress before and after exercise conditioning in patients following surgical revascularization of the myocardium.

Abstract

The main purpose of the study was to evaluate changes in the extent of oxidative stress and its associations with the indices of cardiorespiratory reserve and functional capacity in 35 patients enrolled in a 12-week exercise conditioning programme 2-4 weeks after surgical revascularization of the myocardium. The following markers of oxidative stress were measured spectrophotometrically before and after the programme: lipid peroxidation products (thiobarbituric acid reactive substances, diene conjugates and lipid hydroperoxide) and markers of blood antioxidant status (blood glutathione markers, blood antioxidative capacity and lag phase of low-density lipoprotein (LDL)). To evaluate the functional indices of the cardiorespiratory system the patients underwent bicycle cardiopulmonary testing before entering and after completing the programme. On the basis of peak oxygen consumption (peak VO2) +/- 1 SD, three subgroups with different aerobic capacity were identified: >/=19 ml/min per kg (GR I, n = 7), 11-19 ml/min per kg (GR II, n = 24) and </=11 ml/min per kg (GR III, n = 5). The extent of oxidative stress was markedly elevated in all subgroups. The most significant improvement occurred at the level of lipid peroxidation products and lag phase of LDL. The indices of cardiorespiratory reserve and exercise capacity demonstrated highly significant increases, while the most favourable modifications, considering both the biochemical and functional indices, were observed in patients with the lowest aerobic capacity.