Increasing formation of oxygen reactive species, as a consequence of increasing in the energetic demand, can raise the cellular oxidation state, and it contributes to an optimum cellular redox state and for the development of maximum force. The biological samples reducing power reflects its antioxidant capacity, which is maintained mainly by the low molecular weight antioxidants (LMWA). LMWA act as reducing agents, they donate electrons to radicalar species. They can be, on this way, quantified by electrochemical techniques. LMWA include substances such as uric acid, vitamins C and E vitamin and lipoic acid. The aims of the present work were to investigate the applicability of the surfactant cetilpiridine chloride as a micellar system for the optimization of differential pulse voltammetry technique (DPV) for the analysis of human serum and saliva samples. It was analyzed the correlation of the obtained data with others methodologies. The work is divided in three chapters. Chapter 1 presents a general introduction about the theme, which includes, between other topics: involved molecular mechanisms on physical training adaptation, antioxidant defense system, differential pulse voltammetry and surfactants action. Chapter 2 presents results from serum and saliva samples obtained by DPV technique with and without CPC. Chapter 3 presents data of upper and lower limits from saliva voltamograms of 149 physically active individuals. Acquired data showed that the utilization of cetilpiridine chloride as surfactant increased sensitivity and stability of the voltammetric signal, making possible the use of this method in serum and saliva samples. The use of CCP can replace the polishing and prevent the gradual passivity of the work electrode and loss of voltammetric signal. Our data suggests that the first anodic current peak from both samples is influenced mainly by uric acid concentration. The presented results on this work validate DPV as a methodology to the evaluation of redox state from serum and saliva in response to exercise or pathologic, physiologic conditions. With the saliva antioxidant capacity limits established by DPV method, associated to the use of CPC, it is possible to track, to adequate and to individualize physical training programs, warranting, this way, a correct exercise intensity and maintenance of health and physical integrity.