The influence of training status on oxidative stress in young male handball players Dusica Djordjevic • Dejan Cubrilo • Marija Macura • Nevena Barudzic • Dragan Djuric • Vladimir Jakovljevic Received: 27 October 2010 / Accepted: 10 January 2011 Ó Springer Science+Business Media, LLC. 2011 Abstract Although exercise-induced oxidative stress receives considerable scientific attention, there is still little information available regarding exercise-induced adapta- tions of the antioxidant defence system in adolescent and child athletes. The aim of our study was to establish the effects of long-term exercise training on the redox state of adolescents, and to find correlations between elements of redox homeostasis and aerobic power. Thirty-three handball players and 14 non-athletes, 16–19-years old, were sub- jected to blood sampling to measure levels of nitric oxide (NO; estimated through nitrites (NO 2 – )), superoxide anion radical (O 2 – ), hydrogen peroxide (H 2 O 2 ), lipid peroxidation (estimated through TBARS), superoxide dismutase (SOD) and catalase (CAT). Subjects were also subjected to maxi- mal progressive exercise test to estimate their maximal oxygen consumption (VO 2 max). Athletes had significantly (P \ 0.05) higher SOD activity and lower CAT activity compared with non-athletes (SOD: 2175.52 ± 362.07 compared with 1172.16 ± 747.40 U/g of hemoglobin 9 10 , 3 and CAT: 2.19 ± 0.31 compared with 3.08 ± 0.47 U/g of hemoglobin 9 10 3 ). These differences were the most obvious when comparing non-athletes and athletes with poor/average aerobic power. H 2 O 2 and TBARS levels differed among subjects with poor, average or good aerobic power (P \ 0.01, and P \ 0.05, respectively). Sports engagament and aerobic capacity are important factors in inducing changes in redox status. Keywords Training Á Redox homeostasis Á Oxidative stress Á Nitric oxide Introduction During sports training athletes are continously exposed to various kind of stress. Adaptations to stress occur on numerous levels: from adaptations on subcellular, cellular and tissue level, to adaptations of organs and the whole organism of an athlete. Adaptations to stressors, i.e., structural and functional changes, enable improvement to occur in an athlete’s sports performance. Redox homeostasis occurs when oxidants and antioxi- dants are in balance. If the balance shifts towards higher levels of oxidants, cells are exposed to oxidative stress [1]. Since energy demands and oxygen consumption increase several-fold during exercise, production of reactive oxygen and nitrogen species (RONS) also increases, threatening to disturb redox balance and cause oxidative stress. Oxidative stress induces oxidative damage and inflammation, and it has been suggested to play a primary or secondary role in the development of more than a hundred acute and chronic human diseases [2, 3]. In sports, it is thought that oxidative stress can play a role in the development of symptoms of overtraining including increased fatigue, decreased immune function and decreased performance [4–6]. Today, when efforts are directed toward improved recovery of athletes, dealing with oxidative stress is one of the most important tasks. D. Djordjevic Á D. Cubrilo Á N. Barudzic Á V. Jakovljevic (&) Department of Physiology, Faculty of Medicine, University of Kragujevac, Svetozara Markovica 69, P.P. 124, 34000 Kragujevac, Republic of Serbia e-mail: drvladakgbg@yahoo.com M. Macura Faculty of Sports and Physical Education, University of Belgrade, Belgrade, Republic of Serbia D. Djuric Institute of Medical Physiology ‘‘Richard Burian’’, School of Medicine, Belgrade, Republic of Serbia 123 Mol Cell Biochem DOI 10.1007/s11010-011-0732-6