Insulin-dependent diabetes mellitus (IDDM) is characterized by a metabolic and hormonal disarray that may be more evident during exercise. However, the metabolic response to exercise of different intensities has not been evaluated in IDDM. We therefore used stable isotope techniques and indirect calorimetry to quantify substrate kinetics and oxidation during 30 min of exercise at 45 and 75% of maximal oxygen uptake (Vo2max) in seven men with IDDM (D group) infused with insulin at a constant basal rate. Normal control subjects (C group) matched for age, weight, and Vo2max were also studied. During moderate exercise, glucose uptake (Rd) was lower in the D than in the C group (15.3 ± 1.0 vs. 20.8 ± 1.6 μmol · min−1 · kg−1; P < 0.05). Carbohydrate oxidation also tended to be lower in the D group (71.0 ± 7.2 vs. 87.5 ± 10.6 μmol · min−1 · kg−1; P = 0.08). The D group relied on fat oxidation to a greater extent than did the C group (16.9 ± 1.1 vs. 10.4 ± 1.6 μmol · min−1 · kg−1; P < 0.05). The enhanced fat oxidation was not due to increased lipolysis because no differences occurred in glycerol release (Ra) or in plasma free fatty acid Ra or concentration, and the source of the extra lipid appeared to be intramuscular fat stores. These differences in substrate metabolism were not evident during exercise at 75% of Vo2max. The lower glucose uptake and oxidation in the diabetic subjects during moderate, but not intense, exercise suggest that glucose metabolism is regulated differently depending on exercise intensity. During moderate exercise, glucose uptake into muscle seems to be limiting, and the higher intramuscular triglyceride oxidation observed in IDDM might be a compensatory adaptation needed to maintain energy supply.
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Original Articles|
September 01 1995
Lipid and Carbohydrate Metabolism in IDDM During Moderate and Intense Exercise
Comasia A Raguso;
Comasia A Raguso
Metabolism Unit, Shriners Burns Institute, University of Texas Medical Branch
Galveston, Texas
Departments of Anesthesiology, University of Texas Medical Branch
Galveston, Texas
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Andrew R Coggan;
Andrew R Coggan
Metabolism Unit, Shriners Burns Institute, University of Texas Medical Branch
Galveston, Texas
Departments of Surgery, University of Texas Medical Branch
Galveston, Texas
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Amalia Gastaldelli;
Amalia Gastaldelli
Metabolism Unit, Shriners Burns Institute, University of Texas Medical Branch
Galveston, Texas
Departments of Surgery, University of Texas Medical Branch
Galveston, Texas
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Labros S Sidossis;
Labros S Sidossis
Metabolism Unit, Shriners Burns Institute, University of Texas Medical Branch
Galveston, Texas
Departments of Surgery, University of Texas Medical Branch
Galveston, Texas
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Edward J Bastyr, III;
Edward J Bastyr, III
Departments of Internal Medicine, University of Texas Medical Branch
Galveston, Texas
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Robert R Wolfe
Robert R Wolfe
Metabolism Unit, Shriners Burns Institute, University of Texas Medical Branch
Galveston, Texas
Departments of Anesthesiology, University of Texas Medical Branch
Galveston, Texas
Departments of Surgery, University of Texas Medical Branch
Galveston, Texas
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Address correspondence and reprint requests to Dr. Robert R. Wolfe, Shriners Burns Institute, Metabolism Unit, 815 Market St., Galveston, TX 77550.
1
FFA, free fatty acid; GCMS, gas chromatography–mass spectrometry; IDDM, insulin-dependent diabetes mellitus; m/e, mass-to-charge ratio; PDH, pyruvate dehydrogenase; Ra, rate of appearance; Rd, rate of disappearance; RIA, radioimmunoassay.
Diabetes 1995;44(9):1066–1074
Article history
Received:
January 09 1995
Revision Received:
May 04 1995
Accepted:
May 04 1995
PubMed:
7657030
Citation
Comasia A Raguso, Andrew R Coggan, Amalia Gastaldelli, Labros S Sidossis, Edward J Bastyr, Robert R Wolfe; Lipid and Carbohydrate Metabolism in IDDM During Moderate and Intense Exercise. Diabetes 1 September 1995; 44 (9): 1066–1074. https://doi.org/10.2337/diab.44.9.1066
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