The correlation of oxidative stress with physical performance in cyclists

Abstract

Numerous investigations confirm the appearance of oxidative stress as an effect of intensive physical work and sport training. In comparison there are fewer results on correlation between the character of effort/training and the oxidative stress, especially in respect to the phases of training cycle. The aim of investigation performed was the difference of oxidative stress level in correlation with physical work performance and starting periods. The investigation was performed on cyclists belonging to the Polish National Team (group N) and attending the Secondary Sport School in Wroclaw (group P). The cyclists were investigated in pre-starting and starting periods. In laboratory conditions they performed a standard progressive test on cycle ergometer. Before and during the test there were measured amount of work, heart rate, oxygen uptake, expiratory carbon dioxide, minute ventilation and calculated respiratory quotient RQ. Beside that in blood there were measured the concentrations of malonylodialdehyde (MDA), 4-hydroxyalkenals (4HDA) and lactate, and pH. The results show statistically significant changes of physiological parameters indicating an improvement of physical performance level. The differences between pre-starting and starting periods were greater in the group P. Comparison of the changes in respect to the investigated groups indicate that the physiological cost of physical test was lower in the group N. The oxidative stress level, measured by the concentration of MDA and 4HDA, was higher during the pre-starting period and more distinct in the group P. During the starting period in both groups the level of oxidative stress was similar, statistically insignificant. The results received show that the oxidative stress level is variable during the training related to the phase of training cycle. An elevation of physical performance diminishes the oxidative stress effects, while in the investigated sport discipline the decrease was in little amount correlated with the level of performance.