November 29, 2012

Hormonal response of Exercise in Kids with Type 1 Diabetes


Physical activity is a vital component in the care of diabetes. Although it offers health benefits it presents challenges. This study investigates the VO2 max in  adolescents with Type 1 diabetes.

VO2 max refers to the maximum amount of oxygen that an individual can utilize during intense or maximal exercise.  The hormonal response to physical exercise of different intensities is also measured. Specifically the hormonal levels of GH or growth hormone was measured. GH is also referred to as the ‘fitness hormone’.

Twelve individuals (6 boys and 6 girls) ages 14-19 years old were compared with 12 healthy controls matched for comparable ages, body mass index, pubertal development, and regular fitness level.

On consecutive days, three different workloads were performed in both groups. During the tests, levels of lactate, glucose, insulin, and regulatory hormones [glucagon, cortisol, growth hormone (GH), adrenaline, and noradrenaline] were measured in blood. Subcutaneous glucose was measured continuously.

How different are T1D adolescents and “healthy” kids? Not all that much different. In fact, the VO2 max did not differ between the groups. The hormonal responses discrepancy between the two groups was seen in the GH levels, which peaked in T1D kids around 63 vs. control approximately 33.

GH and insulin do not typically coexist. GH makes energy in the body by protein synthesis and free fatty acids. Insulin uses glucose to make energy in the body.  If energy is needed and insulin is not available GH rises to the occasion. Biologically this makes a lot of sense in people with T1D who cannot produce insulin but have no problem creating GH.

When it comes to physical activity, what people with T1D lack in insulin-producing capacity, we compensate for with a surfeit of growth hormone. It’s an illegal drug for most athletes but with T1D we can get high on own supply.

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