Impact of oxidative stress and smoking on muscle fatigue markers during a single bout of exercise

الملخص EN

Background and hypothesis: Benefits vs.

disadvantages of physical exercise are still controversial particularly with exhaustive physical activity in the light of possible induction of oxidative stress.

Tobacco smoking is another cause of oxidative stress in vivo.

We hypothesized that endurance exercise might induce oxidative stress that causes and would exacerbate muscle fatigue due to the induced aerobic respiration and that smoking would complicate these effects.

Subjects and Methods: 18 male well-trained Physical Education Faculty senior students were randomly selected and grouped into smoker (5 active + 4 passive) and non-smoker (9) student groups.

Plasma was collected immediately before and after a single bout of endurance track running exercise.

A selected number of least invasive plasma indices of muscle fatigue (lactate and activity of lactate dehydrogenase, LDH, and xanthine oxidase, XO), oxidative stress (thiobarbituric acid reactive substances, TBARS, nitric oxide, NO, total iron, Fe*2), antioxidation (total antioxidant activity, TAOA, urate, ascorbate, total zinc, Zn+2, and selenium, Se+2, and superoxide dismutase activity, SOD) were measured using atomic absorption flame photometric and colorimetric techniques, smoking index was calculated and plasma cotinine, the endogenous nicotine metabolic indicator was measured using ELISA technique.

Results: Exercise induced significant increase in muscle fatigue and peroxidative indices (lactate, LDH, XO, TBARS, NO, Fe+2) and significant decrease in Se2+, Zn2* and ascorbate.

There was significant increase in TAOA and SOD and non-significant increase in urate in the two groups.

Smokers showed significantly higher basal peroxidative and lower antioxidation indices compared to nonsmokers, a picture that was exacerbated post-exercise.

This correlated the 5 times higher plasma cotinine level compared to non-smokers.

These changes could not be reflected significantly on indices of exercise and cardiorespiratory endurance.

Conclusions: Endurance exercise induced oxidative stress, despite induced adaptive antioxidants, and exacerbated muscle fatigue that could have systemic and long-term consequences particularly complicated with smoking.