Exercise and Type 1 Diabetes

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Leisure time physical activity is associated with poor glycemic control in type 1 diabetic women: the FinnDiane Study, by J. Wadén and colleagues. Diabetes Care 28:777–782, 2005.

What is the problem and what is known about it so far?

People with diabetes must work to keep their blood glucose as near to normal as possible. Keeping blood glucose at healthy levels can help prevent or delay the start of diabetes problems such as nerve, eye, kidney, and blood vessel damage.

Everyone's blood has some glucose in it because the body needs glucose for energy. Normally, the body breaks food down into glucose and sends it into the bloodstream. Insulin, a hormone made by the pancreas, helps get the glucose from the blood into the cells to be used for energy. In people with type 2 diabetes, the pancreas doesn't make enough insulin or the insulin doesn't work very well. In people with type 1 diabetes, the pancreas no longer makes insulin, so they need insulin shots.

Studies have shown that exercising (as well as eating right and taking diabetes medication) can improve blood glucose control and the body's use of insulin in people with type 2 diabetes. And although studies have shown that people with type 1 diabetes live longer if they exercise, studies have not shown that exercise can improve blood glucose levels and the body’s use of insulin in people with type 1 diabetes.

Why did the researchers do this particular study?

To see whether exercise can improve blood glucose control and the body's use of insulin in people with type 1 diabetes.

Who was studied?

A total of 1,030 people (482 men and 548 women) with type 1 diabetes who took part in the Finnish Diabetic Nephropathy (FinnDiane) Study.

How was the study done?

The people in the study completed a form that that asked questions about the type of exercise they did over the past year. The researchers then measured the patients' blood glucose control, insulin doses, and how well their bodies used insulin.

What did the researchers find?

In this study, the men took part in harder types of exercise, while women exercised more often. The women who did not exercise had worse blood glucose control than the women who did exercise.

The men seemed to use smaller insulin doses when they exercised. The researchers think they used smaller doses to avoid hypoglycemia, or low blood glucose, but taking smaller doses of insulin when exercising makes it harder to control blood glucose over the long term.

The patients who exercised had better measures of how the body uses insulin. Overall, however, the effect of exercise on glucose control, insulin dose, and the body's use of insulin was not large.

What were the limitations of the study?

The design of this study makes it hard to draw conclusions from the results, and the form used in this study so far has not been approved for women with type 1 diabetes.

The study also did not take look at what the patients ate, which could affect a patient's glucose control, insulin dose, and use of insulin.

What are the implications of the study?

For people with type 1 diabetes, there are many possible benefits of exercise. This study showed that women with type 1 diabetes who did not exercise had worse blood glucose control than women with type 1 diabetes who did exercise. Doctors should encourage their patients with diabetes to exercise on a regular basis, but people with type 1 diabetes should consult with their doctor before starting an exercise program. To read about the American Diabetes Association recommendations for exercise and type 1 diabetes, go to http://care.diabetesjournals.org/cgi/content/full/27/suppl_1/s58#SEC4.

FOR MORE INFORMATION

Effects of exercise on the absorption of insulin glargine in patients with type 1 diabetes, by R. Peter and colleagues. Diabetes Care 28:560-565, 2005.

Target-seeking behavior of plasma glucose with exercise in type 1 diabetes, by S.A. Biankin and colleagues. Diabetes Care 26:297-301, 2003.

Physical Activity

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