eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-04-27 6 2 533 536 8669 article Ali Reza Shahsavar 1 Mohammad Javad Pourvaghar 2 Department of Physical Education, University of Payame Noor (PNU) Amol, 46179-33586, Amol, (Iran). Department of Physical Education, Faculty of Humanities, University of Kashan, 873117-51167, Kashan, (Iran). Triiodothyronine (T3) and thyroxine (T4) are both secreted by the thyroid gland in response to thyroid-stimulating hormone (TSH) secreted by the anterior pituitary gland. This research has been conducted in order to study the changes of secretion of thyroid hormone i.e. (T4), (T3), and (TSH) following an aerobic physical activity. A group of 10 male university athletes with over three years experience in different fields of sport participated in this semi- experimental research. The obtained average and standard deviations of factors such as age, height, weight and body mass index (BMI) are as follows: (23.1±1.65), (171.1±4.51), (68.5±4.8) and (21.4±1.1). The exercise training of this research consisted of 20 minutes of running around the track and field, each being 10 rounds in two minutes. The results showed that aerobic activities did not have any significant effect on amount of T3 and TSH secretion, although the results proved a significant difference in concentration level of serum T4 after 20 minutes (4000 m) aerobic physical activity (p = 0.002). So, it seems that aerobic activities can have different reactions on the secretion of thyroid hormone while factors like hematocrit, plasma decrease, as well as changes in PH of blood and also mental conditions may lead to a significant change in concentration of hormone. https://www.biotech-asia.org/vol6no2/the-alteration-of-thyroid-hormone-and-its-stimulating-after-aerobic-physical-activity-on-male-athletes/ Triiodothyronine (T3); Thyroxine (T4); Thyroid-stimulating hormone (TSH); Aerobic exercise