Effects of Acute Exercise on Acetylcarnitine Concentration in Endurance Trained and Untrained Subjects

It has been suggested that imbalance between TCA-cycle flux and β-oxidation may underlie insulin resistance, a predisposing factor for the development of type 2 diabetes mellitus. Acetylcarnitine concentration is suggested to be a marker of such imbalance. It is expected that when TCA-cycle capacity is high (a high oxidative capacity), less acetylcarnitine will accumulate, because of an improved balance between supply and demand of lipids. The major research objective is to examine if acute exercise results in a more pronounced increase in acetylcarnitine concentration in sedentary subjects compared to endurance-trained subjects and if the exercise-induced increase in acetylcarnitine is restored more quickly in endurance-trained subjects when compared to sedentary subjects. The investigators hypothesize that the increase in acetylcarnitine levels will be lower in trained subjects when compared to sedentary subjects, due to a better balance between lipid supply and utilization by the TCA-cycle. Furthermore it is expected that acetylcarnitine concentrations will be restored faster in these trained subjects, because of a tighter regulation of influx of fatty acids. To test this hypothesis the investigators want to compare the acetylcarnitine response to exercise in a group of sedentary subjects and a group of endurance trained subjects. This response will be measured for 30 minutes after exercise with the use of 1H-MRS.