Effects of 8 Weeks Aerobic Training on Plasma Ghrelin Level and Ghrelin Lymphocyte Gene Expression in Elderly Men

Ghrelin is a peptide hormone secreted from the endocrine cells of stomach, affecting feeding behavior, appetite, energy consumption, and body weight. The present study compared the effect of 8 weeks of aerobic training on plasma ghrelin and lymphocyte ghrelin gene expression in elderly men.  In this quasi-experimental study, 30 subjects were selected by convenience sampling method. They were randomly divided into 2 equal groups of aerobic training (n=15) and control (n=15). Aerobic training program included aerobic trainings up to 50-60 minutes at 60-85% of the maximum heart rate, 4 sessions per week which lasted for 8 weeks. After initial assessments (body composition and ghrelin gene expression), followed by 8 weeks of exercise training, post-intervention assessments were completed 48 hours after the last training session. To make intra- and between-group comparisons, repeated measures Analysis of Variance (ANOVA) was used. For all statistical comparisons, the level of significance was set at P<0.05. The Mean±SD age ranges of the study participants were 69.13±3.68 years in the training group and 69.20±4.31 in the control group. Eight weeks of aerobic training significantly reduced BMI from 27.57 to 26.90 kg/m2 (P=0.001), and body fat percentage from 24.31% to 21.43% (P=0.001) in the training group. In addition, lymphocyte ghrelin gene expression significantly increased from 16.87% to 24.92% in the aerobic training group. There was no significant changes in plasma ghrelin levels. Aerobic training through increasing the lymphocyte ghrelin gene expression level and decreasing the values of BMI in middle-aged men, can prevent the incidence of obesity and overweight. It is reasonable to support the role of physical activity as a non-prescriptive therapy in regulating balance and effective peptide hormones in the prevalence of obesity. Therefore, aerobic exercises can be used as a preventive method for the reduction of obesity and the incidence of related diseases.