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Insulin responsiveness in metabolic syndrome after eight weeks of cycle training.
Med Sci Sports Exerc. 2013 Nov; 45(11):2021-9.MS

Abstract

INTRODUCTION

Insulin resistance in obesity is decreased after successful diet and exercise. Aerobic exercise training alone was evaluated as an intervention in subjects with the metabolic syndrome.

METHODS

Eighteen nondiabetic, sedentary subjects, 11 with the metabolic syndrome, participated in 8 wk of increasing intensity stationary cycle training.

RESULTS

Cycle training without weight loss did not change insulin resistance in metabolic syndrome subjects or sedentary control subjects. Maximal oxygen consumption (V·O 2max), activated muscle AMP-dependent kinase, and muscle mitochondrial marker ATP synthase all increased. Strength, lean body mass, and fat mass did not change. The activated mammalian target of rapamycin was not different after training. Training induced a shift in muscle fiber composition in both groups but in opposite directions. The proportion of type 2× fibers decreased with a concomitant increase in type 2a mixed fibers in the control subjects, but in metabolic syndrome, type 2× fiber proportion increased and type 1 fibers decreased. Muscle fiber diameters increased in all three fiber types in metabolic syndrome subjects. Muscle insulin receptor expression increased in both groups, and GLUT4 expression increased in the metabolic syndrome subjects. The excess phosphorylation of insulin receptor substrate 1 (IRS-1) at Ser337 in metabolic syndrome muscle tended to increase further after training in spite of a decrease in total IRS-1.

CONCLUSIONS

In the absence of weight loss, the cycle training of metabolic syndrome subjects resulted in enhanced mitochondrial biogenesis and increased the expression of insulin receptors and GLUT4 in muscle but did not decrease the insulin resistance. The failure for the insulin signal to proceed past IRS-1 tyrosine phosphorylation may be related to excess serine phosphorylation at IRS-1 Ser337, and this is not ameliorated by 8 wk of endurance exercise training.

Authors+Show Affiliations

1Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN; 2Department of Exercise and Sport Science, Clemmer College of Education, East Tennessee State University, Johnson City, TN; and 3Department of Allied Health, College of Clinical and Rehabilitative Health, East Tennessee State University, Johnson City, TN.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Controlled Clinical Trial
Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

23669880

Citation

Stuart, Charles A., et al. "Insulin Responsiveness in Metabolic Syndrome After Eight Weeks of Cycle Training." Medicine and Science in Sports and Exercise, vol. 45, no. 11, 2013, pp. 2021-9.
Stuart CA, South MA, Lee ML, et al. Insulin responsiveness in metabolic syndrome after eight weeks of cycle training. Med Sci Sports Exerc. 2013;45(11):2021-9.
Stuart, C. A., South, M. A., Lee, M. L., McCurry, M. P., Howell, M. E., Ramsey, M. W., & Stone, M. H. (2013). Insulin responsiveness in metabolic syndrome after eight weeks of cycle training. Medicine and Science in Sports and Exercise, 45(11), 2021-9. https://doi.org/10.1249/MSS.0b013e31829a6ce8
Stuart CA, et al. Insulin Responsiveness in Metabolic Syndrome After Eight Weeks of Cycle Training. Med Sci Sports Exerc. 2013;45(11):2021-9. PubMed PMID: 23669880.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Insulin responsiveness in metabolic syndrome after eight weeks of cycle training. AU - Stuart,Charles A, AU - South,Mark A, AU - Lee,Michelle L, AU - McCurry,Melanie P, AU - Howell,Mary E A, AU - Ramsey,Michael W, AU - Stone,Michael H, PY - 2013/5/15/entrez PY - 2013/5/15/pubmed PY - 2014/6/27/medline SP - 2021 EP - 9 JF - Medicine and science in sports and exercise JO - Med Sci Sports Exerc VL - 45 IS - 11 N2 - INTRODUCTION: Insulin resistance in obesity is decreased after successful diet and exercise. Aerobic exercise training alone was evaluated as an intervention in subjects with the metabolic syndrome. METHODS: Eighteen nondiabetic, sedentary subjects, 11 with the metabolic syndrome, participated in 8 wk of increasing intensity stationary cycle training. RESULTS: Cycle training without weight loss did not change insulin resistance in metabolic syndrome subjects or sedentary control subjects. Maximal oxygen consumption (V·O 2max), activated muscle AMP-dependent kinase, and muscle mitochondrial marker ATP synthase all increased. Strength, lean body mass, and fat mass did not change. The activated mammalian target of rapamycin was not different after training. Training induced a shift in muscle fiber composition in both groups but in opposite directions. The proportion of type 2× fibers decreased with a concomitant increase in type 2a mixed fibers in the control subjects, but in metabolic syndrome, type 2× fiber proportion increased and type 1 fibers decreased. Muscle fiber diameters increased in all three fiber types in metabolic syndrome subjects. Muscle insulin receptor expression increased in both groups, and GLUT4 expression increased in the metabolic syndrome subjects. The excess phosphorylation of insulin receptor substrate 1 (IRS-1) at Ser337 in metabolic syndrome muscle tended to increase further after training in spite of a decrease in total IRS-1. CONCLUSIONS: In the absence of weight loss, the cycle training of metabolic syndrome subjects resulted in enhanced mitochondrial biogenesis and increased the expression of insulin receptors and GLUT4 in muscle but did not decrease the insulin resistance. The failure for the insulin signal to proceed past IRS-1 tyrosine phosphorylation may be related to excess serine phosphorylation at IRS-1 Ser337, and this is not ameliorated by 8 wk of endurance exercise training. SN - 1530-0315 UR - https://www.unboundmedicine.com/medline/citation/23669880/Insulin_responsiveness_in_metabolic_syndrome_after_eight_weeks_of_cycle_training_ L2 - https://doi.org/10.1249/MSS.0b013e31829a6ce8 DB - PRIME DP - Unbound Medicine ER -