Background and Purpose: Patients with type 2 diabetes without cardiovascular disease have a reduced exercise capacity compared with nondiabetic subjects. To assesse the impacts of acute exercise on glycemic control, vascular and plasma nitrate/nitrite reaction in type 2 diabetes mellitus (DM) patients. Methods: A total of 46 patients with type 2 DM and 13 control subjects with age, height and weight matched were studied. Based on the HbAIc levels, the DM patients were further divided into two subgroups: poor DM control (PDM, glycosylated hemoglobin (HbAlc≥8.0%) and good DM control (GDM, HbA1c＜8.0%). All patients underwent an incremental exercise test until they exceeded their 90% age-predicated maximal heart rate. Electrocardiogram (ECG) and blood pressure were measured during exercise. The vascular conductivity, plasma nitrate/nitrite and glucose concentration were measured before and immediately after exercise. Results: After exercise, the venous outflow, venous tone, and venous capacity significantly decreased from resting (p＜0.05); However, the venous resistance significantly increased from resting in all groups (p＜0.05). The pairwise comparisons revealed that the patients in the PDM group had lower levels of rest arterial inflow, venous outflow and venous capacity than the GDM group (p＜0.05). Those in the control group had the largest hyperemic arterial inflow among all groups (p＜0.05). Furthermore, the postprandial glucose level was significantly decreased and the plasma nitrate/nitrite level was increased significantly after exercise in the control group (p＜0.05) only, but unchanged in two diabetic subgroups. Conclusion: Poor metabolic control (HbAlc≥8.0%) may cause impairment of vascular regulation and glucose utilization during exercise testing.
