Abstract

Resistance training has been considered as an efficient resource for the control and prevention of pathologies, as well as for the treatment of muscular and joint injuries, rehabilitation of trauma, among others. However, it is known that vigorous physical exercise can increase the formation of free radicals (RL). There are endogenous and exogenous antioxidant mechanisms to combat RL, but when the defense mechanism of the human body is insufficient oxidative stress occurs. The ischemia-reperfusion syndrome, is a mechanism that favors the formation of RL, under these conditions, ammonia is formed and, therefore, it is converted to urea.

Objective: To verify the manifestation of oxidative stress in different intensities of resistance exercise through the expression of plasma urea.

Materials andMethods: Eight volunteers were submitted to two sessions of resistance training, the first one (3series with 8RM x 80% 1RM) and the second one (3 series with 8RMx20% 1RM). Blood samples were obtained before and immediately after the resistance training session to check urea concentrations. The paired Student’s t-test was used, adopting a significance level of 5%.

Result: It was observed that there was a significant increase in urea concentrations after the resistance exercise session at 80% (41.25+8.81vs.47.80+12.81mg/dl). After the 80% 1RM session, plasma urea concentrations were 31.20% higher than the 20% 1RM session.

Conclusion: Intensive resistance exercise (80%1RM) should induce ischemia-reperfusion syndrome, and thus increase the formation of RL, interfering with the degree of biomolecular lesion, which may on the other hand induce important antioxidant adaptations.

Keywords: Resistance training; Oxidative stress; Urea; Free radicals