Oxidants, antioxidants in physical exercise and relation to thyroid function.

Intensive muscular exercise promotes the production of reactive oxygen species (ROS) in the working muscles and can impair athletic performance, particularly in conjunction with inadequate recovery. Mammals are protected against oxygen toxicity by a system of ROS scavengers composed of enzymatic and non-enzymatic components. Although antioxidant supplementation has recently been considered as a means to diminish or prevent damage from ROS, the specific antioxidant requirements of athletes are not known. Since thyroid function is essential for athletic performance, thyroid control should be undertaken in cases where there is any sign of thyroid dysfunction "of unknown etiology". Hyperthyroidism and hypothyroidism have been associated with increased production of ROS as well as related inflammatory response and myopathy. There is evidence that antioxidant supplementation combined with antithyroid treatment with methimazole could be useful in decreasing the oxidative stress.