title: Time course for exercise-induced alterations in insulin action and glucose tolerance in middle-aged people.
abstract: The purposes of this study were 1) to investigate glucose tolerance and insulin action immediately after exercise and 2) to determine how long the improved glucose homeostatic mechanisms observed 12-16 h after exercise persist. Nine (seven men, two women) moderately trained middle-aged (51 +/- 3 yr) subjects performed 45 min of exercise at 73 +/- 2% of peak O2 uptake for 5 days, followed by 7 days of inactivity. Oral glucose tolerance tests (OGTT; 75 g) were performed immediately postexercise (IPE; approximately 30 min) after the final exercise bout and 1, 3, 5, and 7 days after exercise. The incremental area under the plasma glucose curve was markedly higher IPE (355 +/- 82 mM.min) compared with those on days 1 (136 +/- 57 mM.min; P < 0.05) and 3 (173 +/- 62 mM.min; P < 0.05). The glucose area was significantly higher on days 5 (213 +/- 80 mM.min) and 7 (225 +/- 84 mM.min) compared with those on days 1 and 3 (P < 0.05). The incremental insulin area IPE (3,729 +/- 1,104 microU.ml-1.min) was 43% higher compared with that on day 1 (2,603 +/- 635 microU.ml-1.min; P < 0.05) and 66% higher compared with that on day 3 (2,240 +/- 517 microU.ml-1.min; P < 0.05). The insulin area increased to 3,616 +/- 617 microU.ml-1.min after 5 days of inactivity (P < 0.05). An additional 48 h of inactivity did not result in any further increase in the plasma insulin response.(ABSTRACT TRUNCATED AT 250 WORDS)
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: P J
authors.initials: PJ
authors.lastname: Baldus
authors.forename: R L
authors.initials: RL
authors.lastname: Sharp
authors.forename: L D
authors.initials: LD
authors.lastname: Kesl
authors.forename: T L
authors.initials: TL
authors.lastname: Feltmeyer
authors.forename: M S
authors.initials: MS
authors.lastname: Riddle
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition / Q000502:physiology; D004032:Diet; D015444:Exercise / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin