第二型糖尿病為身體各組織對於胰島素敏感度與反應程度下降的一種慢性疾病，與第一型糖尿病不一樣之處為其發展初期與中期血液中的胰島素明顯高於年輕正常時，對於胰島素敏感度的持續退化將造成葡萄糖代謝持續惡化。初期時並無特別的症狀，大多只有出現血糖控制不正常現象。然而，從血糖代謝異常到成為第二型糖尿病患者前稱為糖尿病前期（血糖介於100-125mm/dl間），在此3-5年的期間，血糖值較正常值高，同樣也會出現大、小血管併發症。然而，在此階段除了可透過藥物治療外，更可以改變生活型態來達成防治或延遲成為糖尿病的效果。在改變生活型態的元素中，除了飲食控制及減肥外，運動為不可或缺的重要因子。維持每週至少150分鐘的適度規律運動，將可達到預防糖尿病的效果。

Type 2 diabetes is a chronic metabolic disorder, characterized by impaired whole-body insulin sensitivity and responsiveness. Plasma insulin level of type 2 diabetes patients is increasing above young normal level during early developmental phase, whereas type 1 diabetes patients have extremely low insulin level. Both conditions cause hyperglycemia. Clinical symptom of type 2 diabetes during early developmental phase is generally minimal. Prediabetes is clinically defined as an individual who has fasting glucose level above 100 mg/dL but lower than 126 mg/dL. During this preclinical stage, blood glucose levels is slightly greater than normal, which will subsequently cause vascular complications. In addition to medication, lifestyle intervention is important for preventing further progression from prediabetes to diabetes state. Dietary restriction and exercise are essential components for lifestyle intervention. Regular exercise for more than 150 min per week is generally recommended for diabetes prevention.