The Effect of a Period of Selected Aerobic Training on the Response of Thyroid and Cortisol Hormones to Exhaustive Exercise in Women

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.
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 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).
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.