Study Title:

Exercise Stress and Obesity

Study Abstract

Hypothesis: Basal insulin resistance (IR) and inflammation exacerbate post-exercise oxidative stress (OS) in overweight adolescent girls.

Design: Cross-sectional study, effect of incremental ergocycle exercise until exhaustion on OS markers.

Participants: Normal-weight (control) (n=17, body mass index (BMI): 20–24.2 kg/m2) and overweight adolescent girls (n=29, BMI: 24.1–36.6 kg/m2).

Measurements: Dietary measurement, physical activity assessment (validated questionnaires), fat distribution parameters (by dual-energy X-ray absorptiometry and anthropometry) and maximal oxygen consumption (O2peak). Blood assays include the following: (1) at fasting state: blood cell count, lipid profile, and IR parameters (leptin/adiponectin ratio (L/A), homeostasis model assessment of IR, insulin/glucose ratio; (2) before exercise: inflammation and OS markers (interleukin-6 (IL-6), C-reactive protein (CRP), myeloperoxidase (MPO), reduced glutathione/oxidized glutathione ratio (GSH/GSSG), 15 F2-isoprostanes (F2-Isop), lipid hydroperoxides (ROOH), oxidized low-density lipoprotein (ox-LDL)) and antioxidant status (superoxide dismutase (SOD), glutathione peroxidase (GPX), vitamin C, -tocopherol and -carotene), and (3) after exercise: inflammation and OS markers.

Results: At rest, overweight girls had a deteriorated lipid profile and significantly higher values of IR parameters and inflammation markers, compared with the control girls. These alterations were associated with a moderate rest OS state (lower GSH/GSSG ratio, -tocopherol/total cholesterol (TC) ratio and GPX activity). In absolute values, overweight girls exhibited higher peak power output and oxygen consumption (O2peak), compared with the control girls. Exercise exacerbated OS only in the overweight group (significant increase in F2-Isop, ROOH and MPO). As hypothesized, basal IR and inflammation state were correlated with the post-exercise OS. However, the adjustment of F2-Isop, ROOH and MPO variation per exercise O2 variation canceled the intergroup differences.

Conclusion: In overweight adolescent girls, the main factors of OS, after incremental exhaustive exercise, are not the basal IR and inflammation states, but oxygen overconsumption.

Study Information

H Youssef, C Groussard, J Pincemail, E Moussa3, C Jacob, S Lemoine, M Zind3, J-O Defraigne, J Cillard1, P Delamarche and A Gratas-Delamarche.
Exercise-induced oxidative stress in overweight adolescent girls: roles of basal insulin resistance and inflammation and oxygen overconsumption.
International Journal of Obesity
2009 April
Laboratory 'Mouvement Sport Santé' (EA1274), University of Rennes 2, ENS Cachan, UFR-APS, Rennes Cedex, France.

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