the comparison of t3, t4, tsh, cortisol hormones fluctuations between swimming and running collegiate athletes in one bout of competitive exercise

background: the purpose of this study was to analyze the changes of t3, t4, tsh and cortisol in swimming and running college student athletes after one bout of competitive training session. materials and methods: for this purpose, 15 swimmers by the average age of 22.5±2.48 yrs, height of 177.17±2.31 cm, weight of 68.75±2.24, body mass index (bmi) 21.65±2.14 kg/m2 ) and 15 runner by the average age of 23.33±2.41 yrs, height of 177.5±2.52 cm, weight of 68.5±2.22, body mass index (bmi) 22.01±2.01 kg/m2 ) were selected. the exercise protocols were 200- meter free style swimming for swimmers and 800-meter running for runners. blood samples were taken before and immediately after the exercise to measure t3, t4, tsh and cortisol. the dependent and independent t- tests were used to analyze the statistical data at (p0.05) significant level. results: the results showed a significant increase in t3 and tsh in runners and tsh and cortisol in swimmers. there were no significant changes in other factors. conclusion: based on the results, it can be stated that different factors such as duration and intensity of physical activities, exercise history, body fitness level and the importance of the exercise activity or competition can affect the secretion of catabolic or/and the stress hormones levels, regardless of this fact that the activity takes place in water or on the earth.