A single bout of exercise at higher intensity enhances glucose effectiveness in sedentary men.
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.
Hayashi
Yoichi
Y
Division of Sports Medicine, University of Tsukuba, Ibaraki 305-8574, Japan.
Nagasaka
Shoichiro
S
Takahashi
Nirei
N
Kusaka
Ikuyo
I
Ishibashi
Shun
S
Numao
Shigeharu
S
Lee
Dong Jung
DJ
Taki
Yoko
Y
Ogata
Hitomi
H
Tokuyama
Kumpei
K
Tanaka
Kiyoji
K
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
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