Moderate-intensity training has a better effect on growth factors than high-intensity training in rats

Introduction: Exercise is widely known to be a powerful stimulus to the endocrine system. Several previous studies have examined the effects of exercise on GH, melatonin, or cortisol separately. However, to date, no study has directly examined all three hormones simultaneously within a single exercise protocol, especially using a controlled rat models. Objective: The study aims to determine the effect of moderate-intensity training and high-intensity training on growth determinants in rats. Methodology: A total of 39 male rats, Rattus Norvegicus strain Wistar type, 8 weeks aged, 160±20 gram and randomly divided into three groups: CON (n = 13, controls without treatment), MIT (n = 13, moderate-intensity training, using a treadmill with a speed of 14-16 m/min for 30 minutes and HIT (n = 13, high-intensity training, using a treadmill at a speed of 22-25 m/min during 20 minutes). Treatment was carried out from 17.00-21.00 p.m. with a frequency of 3 times/week for 12 weeks. Blood was taken after 24 hours after the last exercise treatment. Serum measurements of growth hormone (GH), melatonin and cortisol using the ELISA. The data were analyzed by using one way-ANOVA and Tukey’s HSD post hoc test with significant levels of 5%. Results: We observed GH levels in CON (4.30 ± 0.29) pg/mL, MIT (4.55 ± 0.17) pg/mL, HIT (4.09 ± 0.28) pg/mL and (p < 0.001). Melatonin levels in CON (172.31 ± 15.86) pg/mL, MIT (193.54 ± 25.01) pg/mL, HIT (165.96 ± 15.44) pg/mL and (p < 0.05). Cortisol levels in CON (247.22 ± 50.26) ng/mL, MIT (212.82 ± 41.24) ng/mL, HIT (262.11 ± 19.56) ng/mL and (p < 0.05). Conclusions: These findings suggest that moderate-intensity training has a better effect on growth determinants compared to high-intensity training in rats.