Effect of different exercise trainings on β-cell function, insulin resistance, and osteocalcin levels in overweight men

Background and aims: Many findings have shown the potential relation between osteocalcin (OCN) and regulating energy metabolism. Inaddition, it has been revealed that physical activity increases OCN levels. Therefore, the present study aimed to investigate the effects ofdifferent exercise trainings on β-cell function, insulin resistance, and OCN levels in overweight men.Methods: In this study, ۳۳ overweight, young men [Body mass index (BMI): ۲۹.۳۲±۰.۷۵ and age range of ۳۱.۵۰ ± ۲.۲۳] were randomlydivided into control (n = ۱۱), aerobic exercise (n = ۱۱), and resistance exercise (n = ۱۱) groups. Participants of the exercise group were on the۸-week supervised exercise training program for three sessions per week. Weight, body fat percentage, and BMI were analyzed, and thenOCN, insulin, and the homeostasis model assessment of insulin resistance (HOMA-IR) were assessed from fasting blood samples beforeand after the ۸-week exercise program. Finally, data were analyzed by t test and analysis of covariance (ANCOVA).Results: Based on the results, BMI and body weight, insulin, glucose, and HOMA-IR reduced following the exercise (P < ۰.۰۵) whereas serumOCN significantly increased in aerobic exercise (P = ۰.۰۰۱) and resistance exercise (P = ۰.۰۰۰) groups. There were no significant changesin β-cell function in aerobic exercise (P = ۰.۵۱۲) and resistance exercise (P = ۰.۱۶) groups. Pearson correlation analysis demonstrated thatOCN levels were not correlated with HOMA-IR (P = ۰.۷۴۳) and insulin levels (P = ۰.۱۴۳). However, OCN was positively associated withthe homeostasis model assessment of b-cell function (P = ۰.۰۱۴) and glucose (P = ۰.۰۲۵).Conclusion: The results of the present study confirmed that aerobic and resistance exercises cause some changes in body weight andBMI, as well as the OCN and HOMA-IR. Nonetheless, changes in OCN levels were not predictors of changes in insulin secretion frompancreatic beta cells.

Keywords:

Osteocalcin , HOMA-IR , β-cell function , Exercise , Overweight