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Glucose ingestion and substrate utilization during exercise in boys with IDDM
M C Riddell1, O Bar-Or, M Hollidge-Horvat
1Children's Exercise and Nutrition Centre, McMaster University, Hamilton, Ontario, Canada L8N 3Z5.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|April 6, 2000
Summary
Boys with insulin-dependent diabetes mellitus (IDDM) show impaired exogenous glucose (Glu(exo)) oxidation during exercise compared to healthy peers. This reduced utilization persists even with elevated insulin levels, impacting energy supply during physical activity.
Area of Science:
- Exercise Physiology
- Metabolic Research
- Pediatric Endocrinology
Background:
- Insulin-dependent diabetes mellitus (IDDM) affects glucose metabolism.
- Understanding fuel utilization during exercise is crucial for managing diabetes.
- Exogenous glucose oxidation rates in children with IDDM are not well-established.
Purpose of the Study:
- To compare exogenous [(13)C]glucose (Glu(exo)) oxidation in boys with IDDM and healthy boys during submaximal exercise.
- To assess the impact of IDDM on total glucose and fat utilization during cycling.
Main Methods:
- A controlled trial (CT) and a (13)C-enriched glucose trial (GT) were conducted.
- Subjects (boys with IDDM and healthy controls) cycled for 60 minutes at 58.8% of maximal O(2) uptake.
- Total glucose, total fat, and exogenous glucose oxidation were measured using isotopic tracers.
Main Results:
- Exogenous glucose oxidation was significantly lower in boys with IDDM (10.4 g/60 min) compared to healthy boys (14.8 g/60 min).
- Glu(exo) represented a smaller percentage of total energy supply in IDDM (9.0%) versus healthy boys (12.4%).
- Total glucose and fat oxidation did not differ significantly between groups, but endogenous glucose was spared in both.
Conclusions:
- Exogenous glucose oxidation is impaired in exercising boys with IDDM.
- This impairment occurs despite elevated blood glucose and plasma insulin concentrations.
- Reduced Glu(exo) utilization may affect energy availability during physical activity in pediatric IDDM.