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Diabetics Develop Higher Blood Sugar During Exercise


To show this, the researchers tested six diabetic young men who had been diagnosed and treated for type 1 diabetes since childhood. None displayed any evidence of diabetic complications; all had excellent diabetes control, and all engaged regularly in sports and weight training. The researchers took steps to ensure that the diabetics had normal levels of insulin in their blood before exercising, so that their blood sugar was at a healthy level.

The participants underwent cycling tests to the point where they were unable to continue because of muscle exhaustion. They were then compared to other participants in the study who did not have diabetes. By testing people with type 1 diabetes whose blood sugar was healthy before exercise, the researchers found that after the cycle test their blood sugar remained higher when compared to the healthy control group.

Therefore, after exercise, the normal response is to increase insulin to lower the blood sugar released in exercise, Marliss says. "If you are normal, you can compensate by putting out extra insulin," Feld tells WebMD. Type 1 diabetics do not have the ability to increase their production of insulin to counteract the increase in glucose, according to Feld.

Marliss says that currently there is no therapy for a diabetic's body to self-regulate the increased demand for insulin, so the job falls to the diabetic to closely monitor their own sugar levels and adjust the insulin accordingly. "What one would need to do for a person with diabetes," Marliss says, "is to devise a strategy where one would mimic the normal response when the exercise stops, which is that insulin levels go up. There isn't a really good one at this point; therefore, the bottom line is, anybody with diabetes doing intense exercise needs to monitor their sugars even more rigorously than they would with low-intensity exercise, like walking or jogging."

Vital Information:

  • Contrary to conventional wisdom, type 1 diabetics may need to take more insulin, rather than less, following intense exercise.
  • Exercise causes an increase in blood sugar levels, and a person with type 1 diabetes does not produce enough insulin naturally to bring the levels back down.
  • Diabetics need to monitor their blood sugar rigorously when engaging in intense physical activity, even more so than with low-intensity exercise.
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