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Influence of exercise on oxidant stress products in elite Indian cyclists
  1. Chhavi Lekhi1,
  2. Pradeep H Gupta1,
  3. Balwant Singh2
  1. 1
    Department of Biochemistry, Sports Authority of India, Netaji Subas National Institute of Sports (SAI-NSNIS), Patiala, India
  2. 2
    Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, India
  1. Dr C Lekhi, Department of Biochemistry, Sports Authority of India, Netaji Subas National Institute of Sports (SAI-NSNIS), Patiala, India; chhavilekhi{at}


The influence of exercise on free-radical chemistry is not well understood. It is yet to be confirmed whether an adequate biochemical defence system exists in the human body to provide protection from oxy-centred radicals generated by exercise. Fifty trained elite cyclists undertaking exhaustive endurance training were compared with a control group of 50 sedentary workers. Serum malondialdehyde (MDA), uric acid, superoxide dismutase (SOD), catalase, vitamin E, vitamin C and susceptibility to oxidative stress were assessed. Exhaustive exercise resulted in significantly (p<0.05) higher concentrations of serum MDA, vitamin E and vitamin C, significantly (p<0.001) higher SOD activity, but less significantly (p<0.01) higher concentrations of uric acid and significantly (p<0.05) lower catalase activity in elite cyclists than in the controls. Alterations in the activities of erythrocyte scavenger enzymes (SOD) and higher level of non-enzymatic defences in trained subjects may not be sufficient to counteract the increase in reactive oxygen species produced by endurance training.

  • cycling
  • endurance training
  • free radicles
  • oxidative stress
  • defence systems

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  • Competing interests: None.

  • Funding: We are grateful to Sports Authority of India for their financial support.

  • Abbreviations:
    reactive oxygen species
    superoxide dismutase
    maximum oxygen uptake