Document Type: Original Article
MS in exercise physiology, Department of physical education, Marvdasht branch, Islamic Azad University, Marvdasht, Iran
Education Administration in Shiraz
Introduction: Fasting stimulates, whereas glucose suppresses growth hormone (GH) secretion, but the effect of doing exercise in hypo or hyper condition on GH concentration is unclear. The purpose of the present study was to determine exercise induced-changes in GH in hypo and hyperglycemia conditions.
Material & Methods: Eleven non-athletes healthy men (aged: 21.0 ± 2.1 years; body mass index (BMI): 22.6 ± 3.3 kg/m2; mean ± SD) were participated in this study as the subject. At the first week, the subjects were consumed 1 g/kg body weight of glucose in 200 mL water 30 min prior to exercise (hyperglycemia condition) and subsequently walked on a treadmill at 50% of heart rate reserve (HRR) for 60 min. Glucose and GH levels were measured at baseline, immediately and 30 min after the exercise. After a week, the subjects were performed the same exercise after at least 14 h of fasting (hypoglycemia condition) and glucose and GH levels were measured at the same times of the first week.
Results: The results showed that glucose level had not significant changes in response to exercise at the hypoglycemia condition but it was decreased significantly immediately after the exercise at the hyperglycemia condition and it was lower than the baseline until 30 min after the exercise. Repeated measures of ANOVA test showed that there were no significant differences in the GH concentration in the hypo and hyperglycemia conditions at the baseline. The results revealed that GH concentration was increased significantly immediately after the exercise at the hypo and hyperglycemia conditions and the increases of the GH was higher in the hypoglycemia condition in compare to the hyperglycemia condition (P<0.05). GH concentration was returned to the baseline levels 30 min after the exercise at the hypo and hyperglycemia conditions.
Conclusions: In conclusion, it seems that exercise induced-GH is higher in hypoglycemia condition.