The effect of swimming training on hormone levels in girls

Blood samples were taken from nine teenage girl swimmers (ages 13-18 years) at intervals of 4, 12 and 24 years during training. Training intensity and the number of competitions gradually increased through the season. Cortisol and estradiol levels were modified by training but resumed initial values after 24 weeks. At the end of the season testosterone was found to be decreased, whereas ACTH and prolactin had increased. In post-puberals girls (N=4) no irregularities in their menstrual cycles occurred. The relationship between physical exercise and menstrual cycle is discussed it is suggested that, with careful hormone monitoring, it would be possible to avoid menstrual disfunction