Impaired stroke volume and aerobic capacity in female adolescents with type 1 and type 2 diabetes mellitus.
OBJECTIVE
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-vO(2)) 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-vO(2) 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-vO(2) value was not different in any condition.


CONCLUSIONS
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.
Gusso
S
S
Liggins Institute, University of Auckland, 2-6 Park Ave, Grafton, Private Bag 92019, Auckland, New Zealand. s.gusso@auckland.ac.nz
Hofman
P
P
Lalande
S
S
Cutfield
W
W
Robinson
E
E
Baldi
J C
JC
D000293:Adolescent; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism* / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000503:physiopathology*; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D010101:Oxygen Consumption; D013318:Stroke Volume