Effects of a two-month rehabilitation program on substrate utilization during exercise in obese adolescents

Substrate oxidation during exercise: impact of time interval from the last meal in obese women

“…20,21 Furthermore, as previously shown, this type of exercise testing can be used to characterize alterations in substrate utilization in the obese during exercise 6 and has clear beneficial effects. [8][9][10] In this study, the values of W max , expressed in absolute value, in terms of percentage of predetermined W max and in terms of heart rate corresponding to COP ox , were very close to those reported previously in overweight females. 6 The exercise session may appear relatively short (30 min) but this duration is well adapted to the deconditioned state of obese sedentary subjects.…”

“…However, we think that targeting exercise in individuals at a level where they actually oxidize lipids is an improvement in exercise prescription, and we have repeatedly demonstrated that such a training improves after a few weeks the ability to oxidize lipids, which is initially often quite low in obese subjects. 8,9 By contrast, exercise training targeted at intensity levels where the muscle mostly oxidizes CHO improves principally the ability to oxidize CHO. 26 Moreover, this study focuses only on the balance of substrates during an exercise bout, and gives no information on the delayed increase in lipid oxidation that occurs for several hours during recovery, and that may play an important role in the energetic metabolism of subjects submitted to regular exercise training.…”

“…We have demonstrated that the characterization of substrate balance during exercise can be used to prescribe individualized training. 6,8 We further investigated the effects of this type of prescription on obese insulinresistant patients and observed post-training metabolic and ergometric improvements. 9,10 However, the submaximal exercise test used to investigate the substrate balance is performed early in the morning in fasting conditions, whereas exercise training is generally performed in the afternoon in a postprandial period.…”

Training-induced improvement in lipid oxidation in type 2 diabetes mellitus is related to alterations in muscle mitochondrial activity. Effect of endurance training in type 2 diabetes

“…Nevertheless, it is well established that mitochondria are rather adaptable organelles directly involved in substrate oxidation and skeletal muscle can manifest considerable plasticity of mitochondrial activity in response to training in insulin resistant states, as in obese humans [11] or in type 2 diabetic patients, as recently shown [12]. Interestingly, the defect in lipid oxidation found in obese and insulin resistant patients is also very sensitive to training, and rapidly corrected by endurance training targeted at the LIPOXmax [4,13]. It was logic to extend this approach to type 2 diabetes mellitus.…”

“…As previously described by us [3,13,18], we calculated a parameter representative of the whole body lipid oxidation during exercise, which is the maximal lipid oxidation point (LIPOXmax) [3,13,18], expressed in Watts (W), which corresponds to the exercise intensity at which the highest rate of lipid oxidation is measured (lipid oxidation at LIPOXmax, expressed in mg.min -1 ). The difference between before and after training was expressed as ∆lipid oxidation at LIPOXmax.…”