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European Journal of Applied Physiology

, Volume 81, Issue 1–2, pp 67–74 | Cite as

Short-term exercise training improves diaphragm antioxidant capacity and endurance

  • Heather K. Vincent
  • Scott K. Powers
  • Darby J. Stewart
  • Haydar A. Demirel
  • R. Andrew Shanely
  • Hisashi Naito
ORIGINAL ARTICLE

Abstract

These experiments tested the hypothesis that short-term endurance exercise training would rapidly improve (within 5 days) the diaphragm oxidative/antioxidant capacity and protect the diaphragm against contraction-induced oxidative stress. To test this postulate, male Sprague-Dawley rats (6 weeks old) ran on a motorized treadmill for 5 consecutive days (40–60 min · day−1) at approximately 65% maximal oxygen uptake. Costal diaphragm strips were excised from both sedentary control (CON, n=14) and trained (TR, n=13) animals 24 h after the last exercise session, for measurement of in vitro contraction properties and selected biochemical parameters of oxidative/antioxidant capacity. Training did not alter diaphragm force-frequency characteristics over a full range of submaximal and maximal stimulation frequencies (P > 0.05). In contrast, training improved diaphragm resistance to fatigue as contraction forces were better-maintained by the diaphragms of the TR animals during a submaximal 60-min fatigue protocol (P < 0.05). Following the fatigue protocol, diaphragm strips from the TR animals contained 30% lower concentrations of lipid hydroperoxides compared to CON (P < 0.05). Biochemical analysis revealed that exercise training increased diaphragm oxidative and antioxidant capacity (citrate synthase activity +18%, catalase activity +24%, total superoxide dismutase activity +20%, glutathione concentration +10%) (P < 0.05). These data indicate that short-term exercise training can rapidly elevate oxidative capacity as well as enzymatic and non-enzymatic antioxidant defenses in the diaphragm. Furthermore, this up-regulation in antioxidant defenses would be accompanied by a reduction in contraction-induced lipid peroxidation and an increased fatigue resistance.

Key words Diaphragm Oxidative stress Fatigue Lipid peroxidation Antioxidants 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Heather K. Vincent
    • 1
  • Scott K. Powers
    • 1
  • Darby J. Stewart
    • 1
  • Haydar A. Demirel
    • 1
  • R. Andrew Shanely
    • 1
  • Hisashi Naito
    • 1
  1. 1.Department of Exercise and Sport Sciences and Physiology and Center for Exercise and Sports Science, 25 Florida Gym, University of Florida, Gainesville, FL 32611, USA Fax: (352) 392-0316 e-mail: spowers@hhp.ufl.eduUS

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