Abstract

Background and Aim: The effect of exercise training on Thyroid hormone secretion is a controversial topic. This study aimed to investigate the effect of a period of selected aerobic training on thyroxin (T4), Triiodothyronine (T3) and cortisol hormone levels in athlete and non-athlete women after exhaustive exercise sessions was performed. Methods: In a quasi-experimental study with pre and post, among the female volunteers, 20 women whom of which qualified were randomly selected and divided into two athlete (n=10) and non-athlete (n=10) groups. Subjects of both groups did exhaustive exercise (Bruce test) before and after eight weeks of progressive aerobic training (increasing running and climbing stairs with 45 to 85 of maximum heart rate and 3 times in a week). Blood samples were collected immediately after each session of exhaustive exercise and analyzed with a specific kit of the hormone and radio-immunoassay method. In order to compare the means, the paired t-test and one-way analysis of variance followed by Tukey's test was performed. Results: Results indicated that following eight weeks of aerobic training in the athletes group, the T3 (P=0.01) and T4 (P=0.002) hormones' levels in response to exhaustive activity significantly increased but these changes were not significant in non-athletes. On the other hand, the amounts of cortisol in response to this activity significantly decreased in both groups (P =0.04). Conclusion: Overall, results showed that regular aerobic exercise training can adjust cortisol response to physical stress in female athletes and non-athletes. This is while no considerable effect was seen on thyroid hormone levels T3 and T4.