The aim behind the current study was a comparison between salivary cortisol release in rest and training days in male fitness trainers. Methods: In such balanced crossover research, 15 healthy fitness-trained participants (with the mean age, weight and Height of 20.35 ± 1.20 years, 74.15 ± 3.20 kg and 177.30 ± 3.45 cm, respectively) who had a four-year-previous experience in fitness exercise were chosen. While performing the research, the subjects were involved in a fitness training. The

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... l contained three times of fitness training in a week, which would totally be alternative days of "rest" and "exercise" in the period of training. It means that they did training on Monday, Wednesday and Friday, and rested on the other days. To ensure the validity of this study, the participants were selected randomly, in both control and experimental groups. In the meantime, the protocol for fitness exercise was made up of four sets of 15 repetitions utilizing 65% of 1 repetition maximum (1 RM). Within each testing time, saliva samples were taken once in two hours for a maximum of 16 hours. In this study, the ANOVA was followed by a Post-hoc LSD test. Also, the significance level was deemed as (P≤0.05). Results: It was shown that there was a statistically significant addition in the salivary cortisol level right away after the fitness exercise session (P ≤ 0.05). However, no statistically significant difference was observed between exercise and control days in the circadian rhythm of salivary cortisol (P > 0.05). Conclusion: The present research demonstrated that while there was a significant influence of fitness exercise on cortisol right away after exercise, no statistically significant effect has been observed on the circadian secretion of cortisol in fitness sportsmen.