Intervention effect of combined resistance and aerobic exercise on type 2 diabetes: A meta-analysis

BACKGROUND Type 2 diabetes mellitus (T2DM), a chronic metabolic disease with a high global incidence, has become a serious public health challenge. China has the largest number of T2DM patients worldwide, imposing a significant economic burden on the healthcare system. T2DM is closely associated with insulin resistance, impaired pancreatic B cell function, and disordered glucose and lipid metabolism, which can lead to various complications, reducing patients' quality of life and increasing the risk of disability and death. Thus, finding effective preventive and intervention measures is crucial. Exercise therapy, a key part of diabetes management, has gained attention in recent years, with many studies indicating its benefits for blood glucose control and other aspects in diabetic patients. AIM To assess the effectiveness of combined resistance and aerobic exercise interventions on blood glucose control and metabolic indicators in patients with T2DM and to explore their application in diabetes management. METHODS Systematic searches were conducted using PubMed, EMBASE, Cochrane Library, and Chinese databases for relevant randomized controlled trials (RCTs). The inclusion criteria were participants aged ≥ 18 years with T2DM and the intervention involved combined resistance and aerobic exercise for ≥ 8 weeks. The primary outcome indicators were fasting blood glucose, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), glycated hemoglobin A1c (HbA1c), and total cholesterol (TC) levels. Data analysis was performed using RevMan software, and the interventional effects were assessed using weighted mean differences or standardized mean differences (SMD). RESULTS Six RCTs meeting the inclusion criteria were included, with a total sample size of 366 participants. The meta-analysis results showed that combined resistance and aerobic exercise significantly improved several metabolic indicators in patients with T2DM. Specific results were as follows: (1) For fasting blood glucose, combined exercise was more effective than aerobic exercise alone SMD = 1.22; 95% confidence interval (95%CI): 0.70, 1.74; P < 0.00001; (2) LDL-C levels were significantly reduced by the combined intervention (SMD = 1.45; 95%CI: 1.18-1.72; P < 0.00001); (3) The combined intervention significantly increased HDL-C levels (SMD = 1.42; 95%CI: 0.98-1.87; P < 0.00001); (4) The combined intervention significantly reduced TG levels (SMD = 1.12; 95%CI: 0.85-1.39; P < 0.00001; (5) No statistically significant difference was observed in HbA1c between the combined and the aerobic exercise group (SMD = −0.03; 95%CI: -1.09 to 1.04; P < 0.00001); and (6) The combined exercise intervention group significantly reduced TC levels (SMD = 2.66; 95%CI: 1.93-3.38; P < 0.00001). The subgroup analysis results suggest that the effect of exercise interventions may be influenced by various factors, including the patient's age, baseline blood glucose levels, and exercise intensity. CONCLUSION Combined resistance and aerobic exercise intervention significantly improved fasting blood glucose, LDL-C, HDL-C, TG, and TC levels in patients with T2DM, especially in terms of blood glucose control and cardiovascular risk, demonstrating better outcomes than aerobic exercise alone.