Utilization of glycogen but not plasma glucose is reduced in individuals with NIDDM during mild-intensity exercise

• Published in: Journal of applied physiology (1985) 1996-11, Vol.81 (5), p.2027-2033
• Main Authors: Colberg, Sheri R, Hagberg, James M, McCole, Steve D, Zmuda, Joseph M, Thompson, Paul D, Kelley, David E
• Format: Article
• Language: English
• Subjects: Anaerobic Threshold - physiology; Associated diseases and complications; Biological and medical sciences; Blood Glucose - metabolism; Body Composition - physiology; Diabetes Mellitus, Type 2 - metabolism; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Energy Metabolism - physiology; Exercise - physiology; Fatty Acids, Nonesterified - blood; Female; Glycogen - metabolism; Humans; Male; Medical sciences; Middle Aged; Obesity - metabolism; Oxidation-Reduction; Pulmonary Gas Exchange - physiology; Space life sciences
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1996.81.5.2027

Sheri R. Colberg, James M. Hagberg, Steve D. McCole, Joseph M. Zmuda, Paul D. Thompson, and David E. Kelley The Department of Medicine, University of Pittsburgh School of Medicine, and Department of Veterans Affairs Medical Center, Pittsburgh, Pennsylvania 15261 Received 15 December 1995; accepted in final form 7 May 1996. Colberg, Sheri R., James M. Hagberg, Steve D. McCole, Joseph M. Zmuda, Paul D. Thompson, and David E. Kelley. Utilization of glycogen but not plasma glucose is reduced in individuals with NIDDM during mild-intensity exercise. J. Appl. Physiol. 81(4): 2027-2033, 1996. To test the hypothesis that substrate utilization during mild-intensity exercise differs in non-insulin-dependent diabetes mellitus (NIDDM) compared with nondiabetic subjects, seven lean healthy subjects (L), seven obese healthy subjects (O), and seven individuals with NIDDM were studied during 40 min of mild-intensity cycling (40% of peak O 2 uptake). Systemic utilization of plasma glucose (Glc Rd) was determined by using isotope dilution methods. Gas exchange was measured to determine rates of carbohydrate (CHO) and lipid oxidation. During exercise, when CHO oxidation was greater than Glc Rd, the net oxidation of glycogen was calculated as the difference: CHO oxidation   Glc Rd. During mild-intensity cycling, the respiratory exchange ratio was similar across groups (0.87 ± 0.02, 0.85 ± 0.02, and 0.86 ± 0.01 in L, O, and NIDDM subjects, respectively), and CHO oxidation accounted for one-half of total energy expenditure during exercise. Glc Rd increased during exercise and was greatest in subjects with NIDDM (3.0 ± 0.2, 2.9 ± 0.2, and 4.5 ± 0.4 ml · kg 1 · min 1 in L, O, and NIDDM subjects, respectively, P