The Effects of Eight Weeks of Circuit Resistance Training on Serum METRNL Levels and Insulin Resistance in Individuals with Type 2 Diabetes

Purpose The effects of exercise training on meteorin-like protein (METRNL), one of the newest factors involved, is one of the treatment strategies for diabetes. The present study aimed to investigate the effects of circuit resistance training on METRNL and insulin resistance in people with Type 2 Diabetes Mellitus (T2DM). Methods Twenty eligible diabetics volunteered to participate and were randomly divided into control (n = 10, age = 51 ± 1 years, BMI = 27.43 ± 0.98 kg/m 2 ) and experimental groups (n = 10, age = 51 ± 1 years, BMI = 30.12 ± 0.92 kg/m 2 ). The circuit resistance training (10 exercises) used in this study was performed for eight weeks (3 non-consecutive sessions/week, 2–4 circuits, 40%-80% 1RM, 15–6 repetitions). The rest period between each exercise was 20–30 s, and the rest between each circuit was 3 min. Participants in the control groups were asked to maintain their daily physical activities and not to engage in any systematic training program throughout the study. Results METRNL did not change significantly in the control group (0.66 ± 0.06 to 0.7 ± 0.04), but it increased significantly in the experimental group (0.3 ± 0.06 to 0.71 ± 0.03, p = 0.001); In contrast, FBS increased significantly in the control group (122.8 ± 7.5 to 192.8 ± 14.9) and decreased significantly in the experimental group (197.2 ± 7.1 to 135.00 ± 14.00, p = 0.001). Insulin in control and experimental groups did not change significantly (p = 0.96); However, the IR of the control group increased significantly (6.37 ± 1.46 to 9.6 ± 1.53), but its level was significantly attenuated in the experimental group (4.89 ± 1.37 to 4.38 ± 1.44, p = 0.028). Conclusion Eigth weeks of circuit resistance training with low to high intensities can increase the resting levels of METRNL in men with T2DM, which can be significantly associated with the improved fasting blood glucose levels and insulin resistance.