Background: Physical activity (PA) has been shown to improve insulin resistance and other cardiovascular disease risk factors in normal and diabetic adults and in obese youth, but not in non-diabetic, normal-weight children.
Methods: Data from 357 non-diabetic children (10-16 y) were used to examine cross-sectional associations with PA. Insulin sensitivity was assessed with a euglycemic hyperinsulinemic clamp and expressed as M(ffm) (glucose utilization/kg of fat-free mass/min).
Results: Correlations were adjusted for age, sex, race and Tanner stage. PA was significantly correlated with fasting insulin and insulin sensitivity (r=-0.12, P=0.03 and r=0.13, P=0.001, respectively), more strongly in children with above-median systolic blood pressure (r=-0.17, P=0.03 and r=0.35, P=0.0001, respectively). Further adjustment for body mass index, body fat percentage, waist circumference or lipids did not alter these observations.
Conclusions: Physical activity is correlated with lower fasting insulin and greater insulin sensitivity in childhood. These results are consistent with the hypothesis that increasing physical activity among youth may reduce the incidence of type 2 diabetes in children and adolescents.