Exercise is a part of diabetes care

Clinicians recognize that along with diet and, when necessary, medication, exercise is an integral part of the management of type 2 diabetes. Why is exercise important? Because over the short term, it can lower blood sugar, a core goal of diabetes treatment.

But a number of studies have shown that regular exercise can also improve long-term control of blood sugar. Many of these studies, however, have used only a small number of subjects, so their conclusions have not always been consistent. To gain a better understanding of the effect of exercise on both blood sugar and body weight, a group of Canadian researchers sought to address these problems by looking at the combined results of prior studies. Their results appear in a recent Journal of the American Medical Association.

The researchers used a technique known as meta-analysis, a method that mathematically combines the results of a number of studies on the same topic, giving them a larger pool of data to analyze. They looked at studies with an exercise period of at least eight weeks and those that did not involve the use of a diabetic drug.

The shape of a typical exercise plan

The 14 studies included in this analysis involved a total of 504 participants, on average 55 years old, and evenly divided by gender. The typical exercise regimen consisted of three 50-minute sessions a week. Most exercise plans centered on moderate aerobic activity such as walking or cycling, although two studies used resistance training. On average, the exercise program continued for 18 weeks.

To gauge the effectiveness of the exercise plan on blood sugar, the researchers used a blood test known as glycosylated hemoglobin or HbA1c. This test uses changes in red blood cells to provide a measure of blood sugar levels for the previous 8 to 12 weeks.

Movers and shakers see better results

People who successfully completed an exercise program had significantly lower glycosylated hemoglobin levels; the control groups (no exercise) had an average HbA1c of 8.31% while those who exercised had an average of 7.65%, a drop of 0.66%. That may sound like a very small change. In fact, the researchers note that in a United Kingdom trial of intensive glucose-lowering therapy for people with type 2 diabetes, a drop in HbA1c of 0.6% translated into a drop in diabetes-related deaths of 42%. A decrease of this magnitude would also be expected to significantly reduce the risk of diabetic complications.

Exercise was not found to significantly reduce body weight. However, 18 weeks of exercise may not have been long enough for participants to see changes. It is also possible that the volunteers lost fat but gained muscle. Muscle weighs more than fat, so a reduction in fat might not show up on the scale. Finally, even if exercise does not cause weight loss, it can certainly play a role in weight maintenance, preventing further gain.

Exercise is important for everyone's health and well-being. For people with type 2 diabetes, findings such as these offer additional incentive to make physical activity a part of diabetes management. After all, it's an inexpensive and drug-free approach to better health.