RT Journal Article SR Electronic T1 Study of plasma redox biomarkers for accurate stress evaluation in athletes JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 366 OP 367 DO 10.1136/bjsm.2011.084038.160 VO 45 IS 4 A1 M Paes de Barros A1 C O Soares A1 B Pereira A1 E J H Bechara A1 L R Silveira A1 R Curi A1 T P Souza-Junior YR 2011 UL http://bjsm.bmj.com/content/45/4/366.3.abstract AB Background A plethora of data revealed that reactive oxygen species (ROS) are normally produced during/after endurance or resistance exercise. Drastic drops in performance, precocious fatigue and injury risk are putative outcomes of the ROS-mediated biochemical changes. On the other hand, adequate ROS production is essential to provide the desired physiological adaptations of training and to avoid related immune depression. Objective This work aims to test plasma biomarkers of oxidative stress for an accurate evaluation of exhaustion in athletes. Design Subjects were prospectively randomised evaluated. Setting Male cyclists of Brazilian college league (university games) were selected. Participants Subjects (n=20) had no history of smoking, alcohol abuse, or systemic disease. Interventions A Wingate Test was carried out using a Cybex cycle ergometer with increasing loads up to 10% BW (preheat procedure for 5 min). Athletes were strongly encouraged during the test for maximum effort achievement. Main outcome measurements Blood samples (5 ml) were collected before and after the Wingate test, using EDTA-containing Vaccuntainer kits. Total iron, haemoglobin, uric acid, Ferric-reducing activity (FRAP), and malondialdehyde (biomarker of lipid oxidation) were measured in plasma. Results Plasma iron and FRAP levels varied consistently when total amounts released from time zero to 60 min after the Wingate test were evaluated (R=0.939). Remarkably, uric acid was identified as one of the major contributors for FRAP capacity, thus, restricting iron ions participation as catalysts for ROS overproduction during exercise. Lower indexes of lipid oxidation were reported under these circumstances. Conclusion The pool of plasma biomarkers – total iron, FRAP, uric acid and malondialdehyde – are good candidates for an efficient evaluation of oxidative stress related to exhaustion. Further investigations are necessary to precise how responsive those parameters are at different exercise intensities. Financial support: FAPESP, CAPES & CNPq (Brazil); BioReal AB/Fuji Health Sciences (Sweden/Japan).