Reduced decrease of peripheral vascular resistance during exercise in young type I diabetic patients

OBJECTIVE - In normal subjects, peripheral vascular resistance decreases during dynamic exercise. We studied blood pressure and peripheral vascular resistance responses to dynamic exercise in young normotensive type I diabetic patients. RESEARCH DESIGN AND METHODS - Thirty adolescent diabetic patients (9-19 years of age) underwent a maximal exercise test on a cycle ergometer. In a subset of 14 patients, cardiac output was measured by a CO2 rebreathing method and peripheral vascular resistance was calculated Twenty-four normal individuals, age and sex matched, served as control subjects. RESULTS - Diastolic blood pressure was significantly higher in diabetic patients at intermediate workload (77 +/- 2 vs. 71 +/- 1 mmHg) and peak exercise (86 +/- 2 vs. 73 +/- 2 mmHg). Peripheral vascular resistance was significantly higher in diabetic patients at intermediate workload (17.0 +/- 1.1 vs. 12.6 +/- 0.5 mmHg . l(-1) . min(-1) . m(-2)) and peak exercise (16.3 +/- 1.3 vs. 11.4 +/- 0.5 mmHg . l(-1) . min(-1) . m(-2)). There were no significant correlations with the patient's age, diabetes duration, or diabetes control. CONCLUSIONS - We observed the decrease of vasodilator response during dynamic exercise in normotensive young type I diabetic patients.