Tuesday, August 21, 2007

Exercise reduces insulin resistance

This is a study which looked at the effect of an exercise programme on fat kids, trying to stop them from becoming fat diabetic kids. (I hope you don't find that phrase offensive. I was a fat kid myself and it was not nice). Anyway the result was that exercise improved insulin sensitivity, even though it did not change body composition. The lesson here was that exercise had an important benefit metabolically even though there may not have been a change in appearance. It is always worth exercising.

Exercise alone reduces insulin resistance in obese children independently of changes in body composition

(full article available here)

Context: The number of obese children with insulin resistance and type 2 diabetes is increasing but the best management strategy is not clear.

Objective: To assess the effect of a structured eight-week exercise training program on insulin resistance and changes in body composition in obese children.

Design: Eight weeks of structured supervised exercise intervention with outcome measures pre- and post- the exercise period.

Subjects: 14 obese children (12.70 +/- 2.32 yr, 8M, 6F) with high fasting insulin levels were enrolled into the study.

Intervention: Eight weeks of supervised circuit-based exercise training, composed of three fully supervised one-hour sessions per week.

Outcome measures:
These were assessed pre- and post-training program and included insulin sensitivity (euglycaemic-hyperinsulinaemic clamp studies), fasting insulin and glucose levels, body composition using dual energy X-ray absorptiometry (DEXA) scan, lipid profile and liver function tests.

Results: Insulin sensitivity improved significantly after eight weeks of training (Mlbm 8.20 ± 3.44 to 10.03 ± 4.33 mg/kg/min, P < 0.05). Submaximal exercise heart rate responses were significantly lower following the training (p < 0.05), indicating an improvement in cardiorespiratory fitness. DEXA scans revealed no differences in lean body mass or abdominal fat mass.

Conclusion: An eight-week exercise training program increases insulin sensitivity in obese children, and this improvement occurred in the presence of increased cardiorespiratory fitness but is independent of measurable changes in body composition.

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