Acute exercise may exacerbate oxidative stress response in hemodialysis patients.

Background/aims: Hemodialyzed patients (HD) demonstrate elevated oxidative stress (OXS) levels. Exercise effects on OXS response and antioxidant status of HD was investigated in the present study.

Methods: Twelve HD and 12 healthy controls (HC) performed a graded exercise protocol. Blood samples, collected prior to and following exercise, were analyzed for lactate, thiobarbituric acid-reactive substances (TBARS), protein carbonyls (PC), reduced (GSH) and oxidized glutathione (GSSG), total antioxidant capacity (TAC), catalase, and glutathione peroxidase (GPX) activity.

Results: HC demonstrated higher time-to-exhaustion (41%), lactate (41%) and VO2 peak (55%) levels. At rest, HD exhibited higher TBARS, PC, and catalase activity values and lower GSH, GSH/GSSG, TAC, and GPX levels. Although exercise elicited a marked change of OXS markers in both groups, these changes were more pronounced (p < 0.05) in HD patients. After adjusting for VO2 peak, differences between groups disappeared. VO2 peak was highly correlated with GSH/GSSG, TBARS, TAC and PC at rest and after exercise.

Conclusions: These results imply that HD demonstrate higher OXS levels and a lower antioxidant status than HC at rest and following exercise. Acute exercise appears to exacerbate OXS response in hemodialyzed patients probably due to diminished antioxidant defense. However, aerobic capacity level seems to be related to OXS responses in this population.