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摘要
Quantifying the effect size of acute exercise on insulin sensitivity (SIexercise) and simultaneous measurement of glucose disappearance (R-d), endogenous glucose production (EGP), and meal glucose appearance in the postprandial state has not been developed in humans. To do so, we studied 12 healthy subjects [5 men, age 37.1 +/- 3.1 yr, body mass index 24.1 +/- 1.1 kg/m(2), fat-free mass (FFM) 50.9 +/- 3.9 kg] during moderate exercise at 50% (V) over dotO(2max) for 75 min, 120-195 min after a triple-tracer mixed meal consumed at time 0. Tracer infusion rates were adjusted to achieve constant tracer-to-tracee ratio and minimize non-steady-state errors. Glucose turnover was estimated by accounting for the nonstationary kinetics introduced by exercise. Insulin sensitivity index was calculated in each subject both in the absence [time (t) = 0-120 min, SIrest] and presence (t = 0-360 min, SIexercise) of physical activity. EGP at t = 0 min (13.4 +/- 1.1 mu M.kg FFM-1.min(-1)) fell at t = 120 min (2.4 +/- 0.4 mu M.kg FFM-1.min(-1)) and then rapidly rose almost eightfold at t = 180 min (18.2 +/- 2.6 mu M.kg FFM-1.min(-1)) before gradually falling at t = 360 min (10.6 +/- 0.9 mu M.kg FFM-1.min(-1)). R-d rapidly peaked at t = 120 min at the start of exercise (89.5 +/- 11.6 mu M.kg FFM-1.min(-1)) and then gradually declined at t = 195 min (26.4 +/- 3.3 mu M.kg FFM-1.min(-1)) before returning to baseline at t = 360 min. SIexercise was significantly higher than SIrest (21.6 +/- 3.7 vs. 12.5 +/- 2.0 10(-4) dl.kg(-1).min(-1) per mu U/ml, P %26lt; 0.0005). Glucose turnover was estimated for the first time during exercise with the triple-tracer technique. Our results, applying state-of-the-art techniques, show that moderate exercise almost doubles postprandial insulin sensitivity index in healthy subjects.
- 出版日期2013-8
