Réentraînement des maladies métaboliques ciblé individuellement par la calorimétrie d'effort

The effects of aerobic exercise training at two different intensities in obesity and type 2 diabetes: implications for oxidative stress, low-grade inflammation and nitric oxide production

AIMS

To investigate the effect of 16 weeks of aerobic training performed at two different intensities on nitric oxide (tNOx) availability and iNOS/nNOS expression, oxidative stress (OS) and inflammation in obese humans with or without type 2 diabetes mellitus (T2DM).

METHODS

Twenty-five sedentary, obese (BMI > 30 kg/m2) males (52.8 ± 7.2 years); 12 controls versus 13 T2DM were randomly allocated to four groups that exercised for 30 min, three times per week either at low (Fat-Max; 30-40% VO(2max)) or moderate (T(vent); 55-65 % VO(2max)) intensity. Before and after training, blood and muscle samples (v. lateralis) were collected.

RESULTS

Baseline erythrocyte glutathione was lower (21.8 ± 2.8 vs. 32.7 ± 4.4 nmol/ml) and plasma protein oxidative damage and IL-6 were higher in T2DM (141.7 ± 52.1 vs. 75.5 ± 41.6 nmol/ml). Plasma catalase increased in T2DM after T(vent) training (from 0.98 ± 0.22 to 1.96 ± 0.3 nmol/min/ml). T2DM groups demonstrated evidence of oxidative damage in response to training (elevated protein carbonyls). Baseline serum tNOx were higher in controls than T2DM (18.68 ± 2.78 vs. 12.34 ± 3.56 μmol/l). Training at T(vent) increased muscle nNOS and tNOx in the control group only. Pre-training muscle nNOS was higher in controls than in T2DMs, while the opposite was found for iNOS. No differences were found after training for plasma inflammatory markers.

CONCLUSION

Exercise training did not change body composition or aerobic fitness, but improved OS markers, especially when performed at T(vent). Non-diabetics responded to T(vent) training by increasing muscle nNOS expression and tNOx levels in skeletal muscle while these parameters did not change in T2DM, perhaps due to higher insulin resistance (unchanged after intervention).

Two-month effects of individualized exercise training with or without caloric restriction on plasma adipocytokine levels in obese female adolescents

OBJECTIVES

To examine if, in young obese patients, an individualized training programme in association with a caloric restriction programme which had an effect on whole-body lipid oxidation, was able to induce changes on plasma adipocytokine concentrations.

MATERIALS AND METHODS

Twenty-seven obese female adolescents participated in the study. Whole-body lipid oxidation during exercise was assessed by indirect calorimetry during a graded cycle ergometer test. Body mass (BM), body mass index (BMI), percentage of body fat (%BF), insulin homeostasis model assessment (HOMA-IR) and fasting levels of circulating adipocytokines were assessed prior and after a two-month diet programme, individualized training programme targeted at Lipox(max) corresponded to the power at which the highest rate of lipids was oxidized and combined diet/training programme.

RESULTS

The diet/training programme induced both a shift to a higher-power intensity of Lipox(max) (+27.8 + or - 5.1 W; p<0.01) and an increase of lipid oxidation at Lipox(max) (+96.8 + or - 16.2mg/min; p<0.01). The enhancement in lipid oxidation was significantly (p<0.01) correlated with the diet/training-induced improvement in %BF (r = -0.47), HOMA-IR (r = -0.66), leptin (r = -0.41), TNF-alpha (r = -0.48), IL-6 (r = -0.38), adiponectin (r = 0.43) and resistin (r = 0.51).

CONCLUSION

This study showed that in obese female adolescents a moderate training protocol targeted at Lipox(max) and combined with a diet programme improved their ability to oxidize lipids during exercise, and that this improvement was associated with changes in plasma adipocytokine concentrations.