title: Effects of eccentric exercise on insulin secretion and action in humans.
abstract: The effects of an exhaustive bout of eccentric exercise on insulin secretion and action were determined using the hyperglycemic clamp technique. Clamps were performed on eight healthy men after 7 days of inactivity and approximately 36 h after a bout of eccentric exercise. Eccentric exercise consisted of 10 sets of 10 repetitions of combined knee extensions and flexions for each leg at a mean torque 84 +/- 5% of peak concentric torque. During the hyperglycemic clamp procedure, plasma glucose concentration was acutely raised to 10 mmol/l and was maintained near this level for 120 min. Arterialized blood samples were obtained from a heated hand vein to determine plasma glucose and insulin concentrations. Eccentric exercise appeared to produce marked muscle damage, as indicated by a 50-fold increase in plasma creatine phosphokinase (100 +/- 17 vs. 5,209 +/- 3,811 U/l, P < 0.001) and subjective reports of muscle soreness. Peak insulin response during the early phase (0-10 min) of the hyperglycemic clamp was higher after eccentric exercise (183 +/- 38 microU/ml) than after the control clamp (100 +/- 23 microU/ml, P < 0.005). Late-phase (10- to 120-min) insulin response was not altered after eccentric exercise. Peak plasma C-peptide concentrations were higher during the early phase (5.0 +/- 0.7 vs. 4.3 +/- 0.8 ng/ml, P < 0.05) and the late phase (7.5 +/- 0.9 vs. 5.4 +/- 0.6 ng/ml, P < 0.05). Prior eccentric exercise had no significant effect on whole body glucose disposal or glucose disposal rate adjusted for prevailing plasma insulin concentration. These data provide evidence that a single bout of eccentric exercise causes an increase in pancreatic beta-cell insulin secretion in response to hyperglycemia.
authors.affiliation: Department of Health and Human Performance, Iowa State University, Ames 50011.
authors.forename: D S
authors.initials: DS
authors.lastname: King
authors.forename: T L
authors.initials: TL
authors.lastname: Feltmeyer
authors.forename: P J
authors.initials: PJ
authors.lastname: Baldus
authors.forename: R L
authors.initials: RL
authors.lastname: Sharp
authors.forename: J
authors.initials: J
authors.lastname: Nespor
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D002096:C-Peptide / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D004032:Diet; D015444:Exercise / Q000502:physiology*; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D009132:Muscles / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D012420:Running
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D006003:Glycogen; D003402:Creatine Kinase