title: A single bout of exercise at higher intensity enhances glucose effectiveness in sedentary men.
abstract: OBJECTIVE
  Previous studies have shown that glucose effectiveness and insulin sensitivity are acutely enhanced by exercise at various intensities. The aim of this study was to determine the effects of a single bout of exercise at intensities recommended by the American Diabetes Association (ADA) and the American College of Sports Medicine (ACSM) on glucose uptake-specific glucose effectiveness (S(G)(2)*) and insulin sensitivity (S(I)(2)*). S(G)(2)* and S(I)(2)* were estimated by a two-compartment minimal model.
  
  
  METHODS
  Six healthy men (age, 28.5 +/- 2.0 yr) performed a stable-labeled frequently sampled iv glucose tolerance test (FSIGT) under three separate conditions: without any prior exercise, and immediately after single 20-min bouts of cycle ergometer exercise at an intensity of 50% and 70% of maximal oxygen uptake (Vo(2max)). The exercise intensities were close to the lower and upper boundaries recommended by the ADA and ACSM.
  
  
  RESULTS
  Glucose disappearance constant (K(G)), S(G)(2)*, and S(I)(2)* increased after exercise in an intensity-dependent manner. Increases in S(G)(2)* (+237.1 +/- 50.5%), S(I)(2)* (+225.6 +/- 51.9%), and K(G) (+151.7 +/- 16.5%) following exercise at 70% Vo(2max) were statistically significant (P < 0.05), whereas those at 50% Vo(2max) were not.
  
  
  CONCLUSIONS
  In conclusion, a single bout of exercise acutely improves S(I)(2)* and S(G)(2)* in individuals with normal glucose tolerance in an intensity-dependent manner.
authors.affiliation: Division of Sports Medicine, University of Tsukuba, Ibaraki 305-8574, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Nagasaka
authors.forename: Nirei
authors.initials: N
authors.lastname: Takahashi
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Kusaka
authors.forename: Shun
authors.initials: S
authors.lastname: Ishibashi
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Numao
authors.forename: Dong Jung
authors.initials: DJ
authors.lastname: Lee
authors.forename: Yoko
authors.initials: Y
authors.lastname: Taki
authors.forename: Hitomi
authors.initials: H
authors.lastname: Ogata
authors.forename: Kumpei
authors.initials: K
authors.lastname: Tokuyama
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D055372:AMP-Activated Protein Kinases; D000328:Adult; D015444:Exercise; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D051275:Glucose Transporter Type 4; D006801:Humans; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D051275:Glucose Transporter Type 4; D009004:Monosaccharide Transport Proteins; D009097:Multienzyme Complexes; D009124:Muscle Proteins; C495692:SLC2A4 protein, human; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D005947:Glucose