Moindre utilisation des lipides à l’exercice chez le diabétique de type 1

Abstract

Aims We previously demonstrated that type 2 diabetics (not treated by insulin) exhibit at exercise a lower ability to oxidize lipids. Although they usually do not suffer from insulin resistance, type 1 diabetics also exhibit a metabolic disease that might be expected to induce similar disturbances. However, there is a theoretical concern with the measurement of the balance of substrates in insulin-treated patients, since hyperglycemia and insulin treatment are likely to modify the choice of substrates used for oxidation by the exercising muscle. Methods and results We investigated this issue of balance of substrates in insulin-treated diabetics, in 35 type 1 diabetics treated by insulin pump (13 women; 22 men, age 49.7 ± 2; BMI 24.4 ± 0.6) compared to 25 controls undergoing an exercise calorimetry, and assessed the reproducibility of this test in such patients. Under very different conditions of blood glucose control and insulin treatment, this measurement appears to be reproducible. We evidence a decrease in the ability to oxidize the lipids at exercise (left-shift of Brook's point of crossover and LIPOX max, p < 0.001), correlated to duration of diabetes ( r = −0.461; p = 0.006) and urinary albumin excretion rate (UV Alb) ( r = −0.410; p = 0.012). By contrast blood glucose profiles and HbA 1c are not related to lipid oxidation. Conclusion Thus, exercise calorimetry is suitable in insulin-treated patients and shows in these patients an impairment in lipid oxidation with preferential use of carbohydrates, which is correlated with duration of the diabetes and UV Alb, that is, a marker of endothelial dysfunction. This metabolic pattern may result from disease-related sedentarity.