Michael J. McKenzie

Effects of acute aerobic and anaerobic exercise on blood markers of oxidative stress

The purpose of this study was to compare oxidative modification of blood proteins, lipids, DNA, and glutathione in the 24 hours following aerobic and anaerobic exercise using similar muscle groups. Ten cross-trained men (24.3 ± 3.8 years, [mean ± SEM]) performed in random order 30 minutes of continuous cycling at 70% of VO2max and intermittent dumbbell squatting at 70% of 1 repetition maximum (1RM), separated by 1–2 weeks, in a crossover design. Blood samples taken before, and immediately, 1, 6, and 24 hours postexercise were analyzed for plasma protein carbonyls (PC), plasma malondialdehyde (MDA), and whole-blood total (TGSH), oxidized (GSSG), and reduced (GSH) glutathione. Blood samples taken before and 24 hours postexercise were analyzed for serum 8-hydroxy-29-deoxyguanosine (8-OHdG). PC values were greater at 6 and 24 hours postexercise compared with pre-exercise for squatting, with greater PC values at 24 hours postexercise for squatting compared with cycling (0.634 ± 0.053 vs. 0.359 ± 0.018 nM·mg protein-1). There was no significant interaction or main effects for MDA or 8-OHdG. GSSG experienced a shortlived increase and GSH a transient decrease immediately following both exercise modes. These data suggest that 30 minutes of aerobic and anaerobic exercise performed by young, cross-trained men (a) can increase certain biomarkers of oxidative stress in blood, (b) differentially affect oxidative stress biomarkers, and (c) result in a different magnitude of oxidation based on the macromolecule studied. Practical applications: While protein and glutathione oxidation was increased following acute exercise as performed in this study, future research may investigate methods of reducing macromolecule oxidation, possibly through the use of antioxidant therapy.

Gender comparisons of exercise-induced oxidative stress: influence of antioxidant supplementation

The purpose of this study was to determine the influence of gender and antioxidant supplementation on exercise-induced oxidative stress. Twenty-five men and 23 women ran for 30 min at 80% VO2 max, once before and once after 2 weeks of supplementation, and again after a 1-week wash-out period. Subjects were randomly assigned to either placebo (P), antioxidant (A: 400 IU vitamin E+1 g vitamin C), or a fruit and vegetable powder (FV) treatment. Blood was obtained at rest and immediately after exercise. Before supplementation, women had higher resting reduced glutathione, total glutathione, and plasma vitamin E compared with men. With both A and FV supplementations, plasma vitamin E gender differences disappeared. Protein carbonyls, oxidized glutathione, and malondialdehyde all increased similarly for both genders in response to exercise. Both A and FV attenuated the reduced glutathione decrease and the oxidized glutathione and protein carbonyls increase compared with P, with no gender differences. 8-hydroxydeoxyguanosine was lower with treatment A compared with FV and P only for men. Plasma vitamin C increased 39% (A) and 21% (FV) compared with P. These data indicate that women have higher resting antioxidant levels than men. Markers of oxidative stress increased similarly in both genders in response to exercise of similar intensity and duration. Two weeks of antioxidant supplementation can attenuate exercise-induced oxidative stress equally in both genders.