Fitness Is a Determinant of the Metabolic Response to Endurance Training in Adolescents at Risk of Type 2 Diabetes Mellitus

ObjectiveThe purpose of this prospective cohort study was to determine whether changes in cardiorespiratory fitness are associated with the metabolic response to endurance training in adolescents at risk of type 2 diabetes mellitus (T2DM). MethodsSeventy-three overweight and obese adolescents completed a 6-month endurance exercise intervention. Total fat mass, trunk fat mass, visceral adipose tissue, and liver fat were assessed with dual energy X-ray absorptiometry and magnetic resonance imaging spectroscopy. ResultsThe change in cardiorespiratory fitness with training was independently associated with reductions in BMI z-score (=-0.09; P=0.006), total fat mass (=-1.40; P=0.007), trunk fat mass (=-0.70; P=0.01), and liver fat (=-1.80; P=0.053). Adolescents within the highest tertile of change in fitness were 4.67 (95% CI: 1.15-13.73; P=0.03), 11.90 (95% CI: 2.37-59.77; P=0.002), and 6.21 (95% CI: 1.14-33.99; P=0.035) times more likely to experience decreases in body weight, BMI, and liver fat compared with adolescents in the lowest tertile. ConclusionsThe changes in adiposity and hepatic triglyceride content in response to endurance training are significantly related to the increase in cardiorespiratory fitness in adolescents at risk of T2DM.