Postexercise insulin action in African-American women.
African Americans are more insulin resistant than Caucasians. A single bout of moderate-intensity exercise reduces insulin resistance in sedentary Caucasian individuals. The impact of a single bout of exercise on insulin resistance has never been studied in African Americans. The purpose of this experiment was to evaluate the impact of a single bout of exercise on insulin resistance in African-American women.


METHODS
Insulin resistance was assessed in 10 sedentary, over-weight or obese African-American women during a sedentary and exercise condition over a two-day period. During the sedentary condition, participants fasted overnight and sat quietly in the laboratory for 75 minutes. During the exercise condition, participants completed 75 minutes of brisk walking on a treadmill. Ninety minutes following each condition, participants completed an oral glucose tolerance test (OGTT). Three-and-a-half hours later, subjects consumed a standardized meal [meal tolerance test (MTT)].


RESULTS
The insulin response to the OGTT was 18% lower (p=0.046), and insulin sensitivity was 18% higher (p=0.042) in the exercise condition compared to the sedentary condition. There were no differences between conditions following the MTT.


CONCLUSIONS
These results indicate that overweight/obese, sedentary, insulin resistant African-American women had a significant improvement in insulin sensitivity from 75 minutes of brisk walking.
Hasson
Rebecca E
RE
Department of Kinesiology, University of Massachusetts, Amherst, MA 01003, USA.
Freedson
Patty S
PS
Braun
Barry
B
D000328:Adult; D001741:Black or African American; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology