Exercise-Induced Oxidative Stress in Overload Training and Tapering

• Autores: Niels B.J. Vollaard, Chris E. Cooper, Jerry P. Shearman
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 38, Nº. 7, 2006, págs. 1335-1341
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Tapering can be an effective way of enhancing performance after a period of intensive training, but the mechanisms for this ergogenic effect are unclear. It was hypothesized that overload training will increase oxidative stress through an accumulative effect of repeated high-intensity exercise, whereas tapering will improve the antioxidant defense system and alleviate oxidative stress.

    Purpose: To study the oxidative stress response to overload training and tapering.

    Methods: A group of eight well-trained male endurance athletes (30 ± 6 yr; 73 ± 13 kg; 64 ± 6 mL·kg-1·min-1) performed two 4-wk periods of training in a crossover design. Each period included a 2-wk build-up phase followed either by 2 wk of training at the same load (control) or by a week with a 40% increase in training load (overload) preceding a week with a 60% reduction in training load (taper). Performance was monitored through weekly 15-min cycling time trials preceded by a 45-min preload at 70% Wmax. Blood samples were taken before and after the time trials and analyzed for oxidatively modified heme (OxHm), methemoglobin (metHb), and glutathione redox status.

    Results: Cycling time trials induced significant postexercise increases in levels of OxHm (+3.8%; P < 0.001) and oxidized glutathione (GSSG: +13.9%; P < 0.05) and decreases in metHb (-12.1%; P < 0.001), reduced glutathione (GSH: -14.4%; P < 0.001), and GSH/GSSG (-29.7%; P < 0.001). Tapering was shown to significantly increase performance (+4.9%; P < 0.05). Training modifications did not influence resting levels or exercise-induced changes of markers of oxidative stress.

    Conclusion: A short period of tapered training improves performance but does not seem to be associated with substantial changes in exercise-induced oxidative stress.