The effect of exercise training on serum apelin levels and insulin resistance in patients with type 2 diabetes: a systematic review and meta-analysis

Apelin is crucial for regulating energy homeostasis, yet its role in diabetes and insulin resistance remains inadequately understood. This study aimed to investigate the effects of exercise training (Exe) on serum apelin levels and insulin resistance in patients with type 2 diabetes mellitus (T2DM).

A systematic search for relevant studies was conducted using the PubMed, Web of Science, SID, and Magiran databases. Effect sizes and 95% confidence interval (CI) were calculated using a random effects model.

Analysis of 14 interventions involving 386 adults with T2DM indicated that exercise training did not result in a significant change in serum apelin levels [SMD=0.083 (95% CI: 0.731 to 0.897), P=0.8] compared to the control group. However, exercise training was associated with significant reductions in fasting glucose levels [WMD=-19.034 mg/dl (95% CI: -11.69 to -26.37), P=0.001], fasting insulin levels [WMD=-3.616 μU/ml (95% CI: -1.804 to -5.429), P=0.001], and insulin resistance as measured by HOMA-IR [WMD=-1.574 μU/ml (95% CI: -1.104 to -2.044), P=0.001], relative to the control group.

The results of this meta-analysis indicate that exercise training does not significantly affect serum apelin levels. However, it contributes to reductions in fasting glucose, fasting insulin, and insulin resistance in patients with T2DM. Thus, exercise is an effective strategy for improving insulin resistance in individuals with T2DM.