Optimizing Exercise for Type 2 Diabetes Management: Comparative Insights from Aerobic, Resistance, Interval and Combined Training Protocols

<b>Background/Objective</b>: Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance, β-cell dysfunction, and chronic hyperglycemia. Exercise is a cornerstone of non-pharmacological therapy, yet the optimal modalities by which different exercise prescriptions improve metabolic outcomes remain unclear. This review synthesizes evidence on the metabolic effects of aerobic, resistance, high-intensity interval (HIIT), and combined training in individuals with T2DM. <b>Methods</b>: The PubMed, Web of Science, and Scopus databases were searched up to March 30, 2025. A total of 26 articles were included. Articles were selected based on studies conducted on human participants diagnosed with type 2 diabetes mellitus, involving structured exercise interventions, and reporting at least one outcome related to insulin function or glycemic control. <b>Results</b>: This review identified five exercise programs that can improve metabolic outcomes in patients with type 2 diabetes. Evidence levels varied across the 26 studies (<i>n</i> = 20-98), so intensity ranges should be interpreted as indicative rather than prescriptive. Aerobic training was the primary intervention, and evidence from 13 studies (8-48 weeks) showed that moderate-to-vigorous intensity aerobic training (approximately 50-85% of maximum heart rate or 50-75% of VO₂max) was generally associated with improvements in β-cell function, insulin sensitivity, and glycated hemoglobin (HbA1c). Strength training (approximately 40-50% to <3RM, 12 weeks) was linked to better glycemic parameters in some studies, though effects on insulin resistance were inconsistent. Most studies indicated that combined aerobic training (60-85% of maximum heart rate) with resistance or other complementary exercise modalities for 8-24 weeks tended to improve HbA1c, fasting glucose, and insulin sensitivity. High-intensity interval training (HIIT, ≥85% of maximum heart rate, 8 weeks) was also associated with enhanced insulin sensitivity, β-cell function, and basal insulin levels. <b>Conclusions</b>: Different exercise modalities improve metabolic health through complementary mechanisms involving enhanced glucose transport, mitochondrial function, anti-inflammatory effects, and increased muscle mass. Tailoring exercise prescriptions based on individual capacity and metabolic targets may optimize outcomes in T2DM management.