The Effect of one session of resistance training on growth hormone, cortisol and thyroxin: A comparison between fasting and non-fasting conditions

The potential effects of fasting and exercise has been of interest to athletes, coaches and researchers in different fields of sports. Some researchers have investigated the effects of exercise and fasting on blood physiological factors, diabetes, obesity and some hormones. They have found conflicting results. Hormonal changes in training and fasting condition can be important for athletes. The purpose of this study was to investigate the effects of resistance exercise on the rates of catabolic hormones (cortisol, growth hormone and thyroxin) and to compare the results in fasting and non-fasting conditions. 13 students of physical education at Islamic Azad University, Mashhad Branch were selected randomly and participated in this study as a sample. Blood samples were taken from the subjects before and after the exercise, once one week before Ramadan, and for the second time, in the fourth week of Ramadan (the twenty-eighth day). The subjects actively participated in one session of resistance training (stationary weight training). F-test and two-factor ANOVA were used to analyze the data (P≤0.05). 1. Fasting had significant effect on fasting blood glucose and hormone thyroxin. 2. Training had significant effect on growth hormone and cortisol. 3) Fasting and training had no significant mutual effect on any of the variables. Training in fasting condition, probably due to the decreased blood sugar and energy, can create more variation in the levels of catabolic hormones. But, these changes are mostly evident in thyroxin. It is recommended to have more control over the intensity of such trainings during fasting conditions in order to prevent the incidences of hypoglycemia, energy deficit and the hypotrophy of muscle tissues.