Effects of prolonged training on serum thyrotropin and thyroid hormones in elite strength athletes

The response of the pituitary-thyroid system was studied in 11 elite weight lifters before, during and after a strength training period of 1 year. During the overall 1 year training period, no systematic changes were found in the concentrations of serum thyrotropin (TSH), thyroxine (T4), free thyroxine (FT4), tri-iodothyronine (T3) and thyroxine binding globulin (TBG). During the pre-competition training period (weeks 15-18), there was a decreased volume of training which was accompanied by a gradual increase in serum T4, FT4 and T3 concentrations. When the intensity of training increased and volume decreased further before the main competition (weeks 19-20), the changes noted returned to their initial levels. It was concluded that in elite strength athletes, intensive training with one training session per day does not lead to major changes in pituitary-thyroid function, but only to minor physiological responses well within the normal range.