title: Oxidative stress biomarkers responses to physical overtraining: implications for diagnosis.
abstract: Overtraining syndrome is characterized by declining performance and transient inflammation following periods of severe training with major health implications for the athletes. Currently, there is no single diagnostic marker for overtraining. The present investigation examined the responses of oxidative stress biomarkers to a resistance training protocol of progressively increased and decreased volume/intensity. Twelve males (21.3+/-2.3 years) participated in a 12-week resistance training consisting of five 3-week periods (T1, 2 tones/week; T2, 8 tones/week; T3, 14 tones/week; T4, 2 tones/week), followed by a 3-week period of complete rest. Blood/urine samples were collected at baseline and 96 h following the last training session of each period. Performance (strength, power, jumping ability) increased after T2 and declined thereafter, indicating an overtraining response. Overtraining (T3) induced sustained leukocytosis, an increase of urinary isoprostanes (7-fold), TBARS (56%), protein carbonyls (73%), catalase (96%), glutathione peroxidase, and oxidized glutathione (GSSG) (25%) and a decline of reduced glutathione (GSH) (31%), GSH/GSSG (56%), and total antioxidant capacity. Isoprostanes and GSH/GSSG were highly (r=0.764-0.911) correlated with performance drop and training volume increase. In conclusion, overtraining induces a marked response of oxidative stress biomarkers which, in some cases, was proportional to training load, suggesting that they may serve as a tool for overtraining diagnosis.
authors: Department of Physical Education and Sports Science, Democritus University of Thrace, Komotini 69100, and Department of Internal Medicine, Henry Dunant Hospital, Athens, Greece.
authors: Konstantinos
authors: K
authors: Margonis
authors: Ioannis G
authors: IG
authors: Fatouros
authors: Athanasios Z
authors: AZ
authors: Jamurtas
authors: Michalis G
authors: MG
authors: Nikolaidis
authors: Ioannis
authors: I
authors: Douroudos
authors: Athanasios
authors: A
authors: Chatzinikolaou
authors: Asimina
authors: A
authors: Mitrakou
authors: George
authors: G
authors: Mastorakos
authors: Ioannis
authors: I
authors: Papassotiriou
authors: Kiriakos
authors: K
authors: Taxildaris
authors: Dimitrios
authors: D
authors: Kouretas
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism; D015415:Biomarkers / Q000032:analysis / Q000097:blood / Q000652:urine; D005978:Glutathione / Q000097:blood / Q000378:metabolism / Q000652:urine; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000378:metabolism*; D018384:Oxidative Stress; D010807:Physical Endurance
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D005978:Glutathione