Impaired stroke volume and aerobic capacity in female adolescents with type 1 and type 2 diabetes mellitus

Abstract

Aim/hypothesis: This study was designed to determine whether type 2 diabetic adolescents have reduced aerobic capacity and to investigate the role of cardiac output and arteriovenous oxygen difference (a-vO2) in their exercise response. Methods: Female adolescents (age 12-18 years) with type 2 diabetes mellitus (n=8) and type 1 diabetes mellitus (n=12) and obese (n=10) and non-obese (n=10) non-diabetic controls were recruited for this study. Baseline data included maximal aerobic capacity (cycle ergometer) and body composition. Cardiac output and a-vO2 were determined at rest and during submaximal exercise. Results: Diabetic groups had lower aerobic capacity than non-diabetic groups (p<0.05). Adolescents with type 2 diabetes had lower aerobic capacity than the type 1 diabetic group. Maximal heart rate was lower in the type 2 diabetic group (p<0.05). Exercise stroke volume was 30-40% lower at 100 and 120 beats per min in the diabetic than in the non-diabetic groups (p<0.05). The a-vO2 value was not different in any condition. Conclusions and interpretation: Type 2 diabetic adolescents have reduced aerobic capacity and reduced heart rate response to maximal exercise. Furthermore, type 2 and type 1 diabetic adolescent girls have a blunted exercise stroke volume response compared with non-diabetic controls. Central rather than peripheral mechanisms contribute to the reduced aerobic capacity in diabetic adolescents. Although of short duration, type 2 diabetes in adolescence is already affecting cardiovascular function in adolescents. © 2008 Springer-Verlag.