Aim: The purpose of this investigation was to evaluate the oxidative stress response to aerobic exercise at high and moderate intensities.
Methods: Twenty healthy untrained men were randomly allocated into two groups: moderate intensity (MI) and high intensity (HI). Subjects of group MI and HI ran on the treadmill for 30-minutes at a running speed corresponding to 60% and 75% VO(2max) respectively. Blood lactate (LA) was measured before and immediately after the exercise. The subjective rate of perceived exertion (RPE) was obtained at the end of the trail. Venous blood samples were obtained before the exercise, immediately, 2 h, and 24 h after exercise. Blood samples were analyzed for malondialdehyde (MDA), as a biomarker of lipid peroxidation; uric acid (UA) as an intrinsic antioxidant; creatinin kinase (CK) activity, as a biomarker of muscle damage as well as total and differential leucocytes, as biomarkers of inflammation. The pattern of RPE was not significantly influenced by intensity of exercise.
Results: There was no significant difference in LA, CK, MDA, UA, and total and differential leukocytes between two groups (P>0.05). MDA was increased 2 h after exercise only in group HI (P<0.05). Plasma UA concentrations and CK activities were significantly greater than pre-exercise in immediately and 2 h after exercise in both groups (p<0.05). Exercise resulted in significant leukocytosis immediately after exercise in both groups and 2 h after exercise only in group HI (P<0.05), returning to pre-exercise levels after 24 h just in group MI. Neutrophil counts were increased 2 h after exercise in both groups and 24 h after exercise only in group HI (P<0.05). Monocyte counts were increased 2 h after exercise only in group HI (P<0.05).
Conclusion: These data suggest that exercise with moderate intensity causes less lipid peroxidation and inflammation in comparison with high intensity exercise.