Differential impact of acute bout of exercise on redox- and oxidative damage-related profiles between untrained subjects and amateur runners.

Despite the demonstrated exercise-induced increase in reactive oxygen species (ROS) production, growing epidemiological evidence indicates that habitual, moderate physical activity reduces the incidence of several oxidative stress-based diseases. This apparent paradox can be explained taking into account that ROS produced during repeated exercise bouts may act as mild stressors able to trigger physiological and biomolecular hormetic responses through a number of redox-sensitive transcription pathways. Unfortunately, much more limited information is available from general population-based research, which could better reflect the condition of common people interested in achieving and maintaining good fitness levels. The present work aimed at investigating whether and how exercise-related habits in non-professional regular runners (n=33) can affect the systemic anti-oxidative capacity, and the resting serum levels of typical lipid peroxidation-related by-products and oxidatively-damaged proteins, in comparison with untrained sedentary individuals (n=25). We also analyzed in both groups the redox response elicited by a modified Bruce-based maximal exercise test on the same parameters. Our findings indicated that long-term regular and moderate practice of aerobic physical activity can increase antioxidant defense systems, lower the resting protein oxidation processes and reduce the immediate up-regulation of lipid-targeting oxidative stress in response to an acute bout of exercise.

Aerobic performance and antioxidant protection in runners.

Reactive oxygen species (ROS) production is known to increase as a result of muscular contractile activity and this phenomenon may perturb the fine-controlled cellular redox homeostasis within cells and tissues. We studied the possible correlations between individual aerobic performance-related factors and the oxidative stress markers profile in the serum of thirty-five endurance male runners that experienced a modified Bruce-based maximal graded exercise test. Our investigation assessed the systemic levels of malondialdehyde (MDA), protein carbonyl content (PCC) and total antioxidant status (TAS). We found that redox-related parameters and aerobic performance indicators were correlated. Indeed, significant negative associations between TAS and PCC (r-value -0.7, p<0.001) and between TAS and total protein content (r-value -0.4, p=0.005) were observed. A significant positive association between total protein and PCC (r-value 0.4, p=0.012) was also revealed. Only a trend of negative correlation between serum total protein and anaerobic threshold (r-value -0.3, p=0.07) was found. Interestingly, different responses in MDA levels were elicited by the ergometric test as a function of the individual anaerobic threshold. High aerobic capacities may be promising anthropometric factors indicative of adapted biochemical environments featuring enhanced protection against the oxidative challenge elicited by both regular endurance training and single intense exercise bouts.